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AuthorTitleYearJournal/ProceedingsReftypeDOI/URL
Abdeddaïm, Y., Chandarli, Y., Davis, R.I. and Masson, D. Response time analysis for fixed priority real-time systems with energy-harvesting 2016 Real-Time Systems
Vol. 52(2), pp. 125-160 
article URL 
Abstract: This paper introduces sufficient schedulability tests for fixed-priority pre-emptive scheduling of a real-time system under energy constraints. In this problem, energy is harvested from the ambient environment and used to replenish a storage unit or battery. The set of real-time tasks is decomposed into two different types of task depending on whether their rate of energy consumption is (i) more than or (ii) no more than the storage unit replenishment rate. We show that for this task model, where execution may only take place when there is sufficient energy available, the worst-case scenario does not necessarily correspond to the synchronous release of all tasks. We derive sufficient schedulability tests based on the computation of worst-case response time upper and lower bounds. We show that these tests are sustainable with respect to decreases in the energy consumption of tasks, and increases in the storage unit replenishment rate. Further, we show that Deadline Monotonic priority assignment is optimal with respect to the derived tests. We examine both the effectiveness and the tightness of the bounds, via an empirical investigation.
BibTeX:
@article{Abdeddaim2016,
  author = {Abdeddaïm, Yasmina and Chandarli, Younès and Davis, Robert Ian and Masson, Damien},
  title = {Response time analysis for fixed priority real-time systems with energy-harvesting},
  journal = {Real-Time Systems},
  year = {2016},
  volume = {52},
  number = {2},
  pages = {125--160},
  url = {/papers/Abdeddaim2016.pdf}
}
Abdeddaïm, Y., Chandarli, Y. and Masson, D. The Optimality of PFPasap Algorithm for Fixed--Priority Energy-Harvesting Real-Time Systems 2013 Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS), pp. 47-56School: Université Paris--Est Marne-la-Vallée -- ESIEE  inproceedings  
Abstract: The paper addresses the real--time xed-priority scheduling problem for battery-powered embedded systems whose energy storage unit is replenished by an environmental energy source. In this context, a task may meet its deadline only if its cost of energy can be satis ed early enough. Hence, a scheduling policy for such a system should account for properties of the source of energy, capacity of the energy storage unit and tasks cost of energy. Classical fixed-priority schedulers are no more suitable for this model. Based on these motivations, we propose PFPasap an optimal scheduling algorithm that handles both energy and timing constraints. Furthermore, we state the worst case scenario for non concrete tasksets scheduled with this algorithm and build a necessary and su cient feasibility condition for non concrete tasksets. Moreover, a minimal bound of the storage unit capacity that keeps a taskset schedulable with PFPasap is also proposed. Finally, we validate the proposed theory with large scale simulations and compare our algorithm with other existing ones.
BibTeX:
@inproceedings{Abdeddaim2013,
  author = {Abdeddaïm, Yasmina and Chandarli, Younès and Masson, Damien},
  title = {The Optimality of PFPasap Algorithm for Fixed--Priority Energy-Harvesting Real-Time Systems},
  booktitle = {Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS)},
  school = {Université Paris--Est Marne-la-Vallée -- ESIEE},
  year = {2013},
  pages = {47--56}
}
Abdeddaïm, Y. and Masson, D. Real--Time Scheduling of Energy Harvesting Embedded Systems with Timed Automata 2012 Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 31-40  inproceedings DOI URL 
Abstract: In this paper, we propose feasibility and schedulability tests for a real--time scheduling problem under energy constraints. We first introduce the problem and show how to model it using timed automata. We then propose a feasibility test based on CTL model checking and schedulability tests for EDF and Preemptive Fixed Priority algorithms (PFP). Our approach also permits to generate a feasible schedule if one exists or otherwise to find how to correct battery characteristics to make the problem feasible. It is finally possible to generate schedules that optimize some criteria, such as the number of context switches between the battery recharging and discharging modes, the minimal and the maximal energy levels reached during the execution, or the number of preemptions. The approach is illustrated by some experiments using the model checking tool UPAAL [1].
BibTeX:
@inproceedings{Abdeddaim2012,
  author = {Abdeddaïm, Yasmina and Masson, Damien},
  title = {Real--Time Scheduling of Energy Harvesting Embedded Systems with Timed Automata},
  booktitle = {Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {31--40},
  url = {papers/Abdeddaim2012.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2012.21}
}
Addisu, A., George, L., Sciandra, V. and Agueh, M. Mixed Criticality Scheduling Applied to JPEG2000 Video Streaming Over Wireless Multimedia Sensor Networks 2013 Proceedings of the 1st International Workshop on Mixed Criticality Systems (WMCS), pp. 55-60  inproceedings URL 
Abstract: In this paper, we propose a mixed--criticality scheduling scheme for selection of JPEG2000 codestream features to be transmitted over Wireless Multimedia Sensor Networks (WMSNs). We extend the application of mixed-criticality scheduling model to the wireless domain. We show that by adopting mixed-criticality scheduling scheme, an improved end-to-end response time is gained with respect to the classical case where all information exhibit the same level of importance.
BibTeX:
@inproceedings{Addisu2013,
  author = {Addisu, Alemayehu and George, Laurent and Sciandra, Vincent and Agueh, Max},
  title = {Mixed Criticality Scheduling Applied to JPEG2000 Video Streaming Over Wireless Multimedia Sensor Networks},
  booktitle = {Proceedings of the 1st International Workshop on Mixed Criticality Systems (WMCS)},
  year = {2013},
  pages = {55--60},
  url = {papers/WMCSProceedings2013.pdf}
}
Allavena, A. and Mossé, D. Scheduling of Frame-based Embedded Systems with Rechargeable Batteries 2001 Proceedings of the International Workshop on Real-Time and Embedded System  inproceedings URL 
BibTeX:
@inproceedings{Allavena2001,
  author = {Allavena, André and Mossé, Daniel},
  title = {Scheduling of Frame-based Embedded Systems with Rechargeable Batteries},
  booktitle = {Proceedings of the International Workshop on Real-Time and Embedded System},
  year = {2001},
  url = {/papers/Allavena2001.pdf}
}
Altmeyer, S., Cucu-Grosjean, L. and Davis, R.I. Static probabilistic timing analysis 2015 Real-Time Systems
Vol. 51(1), pp. 77-123 
article  
Abstract: In this paper, we investigate Static Probabilistic Timing Analysis (SPTA) for single processor real-time systems that use a cache with an evict-on-miss random replacement policy. We show that previously published formulae for the probability of a cache hit can
produce results that are optimistic and unsound when used to compute probabilistic WorstCase Execution Time (pWCET) distributions.
We investigate the correctness, optimality, and precision of different approaches to SPTA for random replacement caches. We prove that one of the previously published formulae for the probability of a cache hit is optimal with respect to the limited information (reuse distance
and cache associativity) that it uses. We derive an alternative formulation that makes use of additional information in the form of the number of distinct memory blocks accessed (the stack distance). This provides a complementary lower bound that can be used together with previously published formula to obtain more accurate analysis. We improve upon this joint approach by using extra information about cache contention. To investigate the precision of various approaches to SPTA, we introduce a simple exhaustive method that computes a precise pWCET distribution, albeit at the cost of exponential complexity. We integrate this precise approach, applied to small numbers of frequently accessed memory blocks, with imprecise analysis of other memory blocks, to form a combined approach that improves precision, without significantly increasing complexity. The performance of the various approaches are compared on benchmark programs. We also make comparisons against deterministic analysis of the Least Recently Used (LRU) replacement policy.
BibTeX:
@article{Altmeyer2015,
  author = {Altmeyer, Sebastian and Cucu-Grosjean, Liliana and Davis, Robert Ian},
  title = {Static probabilistic timing analysis},
  journal = {Real-Time Systems},
  year = {2015},
  volume = {51},
  number = {1},
  pages = {77--123}
}
Anderson, J.H., Bud, V. and Devi, U.C. An EDF--based restricted-migration scheduling algorithm for multiprocessor soft real-time systems 2008 Real--Time Systems
Vol. 38(2), pp. 85-131 
article DOI URL 
Abstract: There has been much recent interest in the use of the earliest--deadline-first (EDF) algorithm for scheduling soft real-time sporadic task systems on identical multiprocessors. In hard real-time systems, a significant disparity exists between EDF-based schemes and Pfair scheduling: on M processors, the worst-case schedulable utilization for all known EDF variants is approximately M/2, whereas it is M for optimal Pfair algorithms. This is unfortunate because EDF -based algorithms entail lower scheduling and task-migration overheads. However, such a disparity in schedulability can be alleviated by easing the requirement that all deadlines be met, which may be sufficient for soft real-time systems. In particular, in recent work, we have shown that if task migrations are not restricted, then EDF (i.e. , global EDF) can ensure bounded tardiness for a sporadic task system with no restrictions on total utilization. Unrestricted task migrations in global EDF may be unappealing for some systems, but if migrations are forbidden entirely, then bounded tardiness cannot be guaranteed. In this paper, we address the issue of striking a balance between task migrations and system utilization by proposing an algorithm called EDF-fm, which is based upon EDF and treads a middle path, by restricting, but not eliminating, task migrations. Specifically, under EDF-fm , the ability to migrate is required for at most M−1 tasks, and it is sufficient that every such task migrate between two processors and at job boundaries only. EDF-fm, like global EDF, can ensure bounded tardiness to a sporadic task system as long as the available processing capacity is not exceeded, but, unlike global EDF, may require that per-task utilizations be capped. The required cap is quite liberal, hence, EDF-fm should enable a wide range of soft real-time applications to be scheduled with no constraints on total utilization.
BibTeX:
@article{Anderson2008,
  author = {Anderson, James H. and Bud, Vasile and Devi, UmaMaheswari C.},
  title = {An EDF--based restricted-migration scheduling algorithm for multiprocessor soft real-time systems},
  journal = {Real--Time Systems},
  year = {2008},
  volume = {38},
  number = {2},
  pages = {85--131},
  url = {papers/Anderson2008.pdf},
  doi = {http://doi.org/10.1007/s11241--007-9035-0}
}
Anderson, J.H., Bud, V. and Devi, U.C. An EDF--based Scheduling Algorithm for Multiprocessor Soft Real-Time Systems 2005 Proceedings of the 17th Euromicro Conference on Real--time Systems (ECRTS), pp. 199-208  inproceedings DOI URL 
Abstract: We consider the use of the earliest--deadline-first (EDF) scheduling algorithm in soft real-time multiprocessor systems. In hard real-time systems, a signi¯cant disparity exists between EDF-based schemes and Pfair scheduling (which is the only known way of optimally scheduling recurrent real-time tasks on multiprocessors): on M processors, all known EDF variants have utilization-based schedulability bounds of approximately M=2, while Pfair algorithms can fully utilize all processors. This is unfortunate because EDF-based algorithms entail lower scheduling and task-migration overheads. In work on hard real-time systems, it has been shown that this disparity in schedulability can be lessened by placing caps on per-task utilizations. In this paper, we show that it can also be lessened by easing the requirement that all deadlines be met. Our main contribution is a new EDF-based scheme that ensures bounded deadline tardiness. In this scheme, per-task utilizations must be capped, but overall utilization need not be restricted. The required cap is quite liberal. Hence, our scheme should enable a wide range of soft real-time applications to be scheduled with no constraints on total utilization. We also propose techniques and heuristics that can be used to reduce tardiness. To the best of our knowledge, this paper is the ¯rst to examine multiprocessor EDF scheduling in the context of soft real-time systems.
BibTeX:
@inproceedings{Anderson2005,
  author = {Anderson, James H. and Bud, Vasile and Devi, UmaMaheswari C.},
  title = {An EDF--based Scheduling Algorithm for Multiprocessor Soft Real-Time Systems},
  booktitle = {Proceedings of the 17th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2005},
  pages = {199--208},
  url = {papers/Anderson2005.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2005.6}
}
Anderson, J.H. and Srinivasan, A. Early--Release Fair Scheduling 2000 Proceedings of the 12th Euromicro Conference on Real--time Systems (ECRTS), pp. 35-43  inproceedings DOI URL 
Abstract: We present a variant of Pfair scheduling, which we call early--release fair (ERfair) scheduling. Like conventional Pfair scheduling, ERfair scheduling algorithms can be applied to optimally schedule periodic tasks on a multiprocessor system in polynomial time. However, ERfair scheduling differs from Pfair scheduling in that it is work conserving. As a result, average job response times may be much lower under ERfair scheduling than under Pfair sche duling, particularly in lightly-loaded systems. In addition, runtime costs ar e lower under ERfair scheduling.
BibTeX:
@inproceedings{Anderson2000,
  author = {Anderson, James H. and Srinivasan, Anand},
  title = {Early--Release Fair Scheduling},
  booktitle = {Proceedings of the 12th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2000},
  pages = {35--43},
  url = {papers/Anderson2000.pdf},
  doi = {http://doi.org/10.1109/EMRTS.2000.853990}
}
Andersson, B. Static--priority scheduling on multiprocessors 2003 School: Chalmers University of Technology  phdthesis URL 
Abstract: This thesis deals with the problem of scheduling a set of tasks to meet deadlines on a computer with multiple processors. Static--priority scheduling is considered, that is, a task is assigned a priority number that never changes and at every moment the highestpriority tasks that request to be executed are selected for execution. The performance metric used is the capacity that tasks can request without missing a deadline. It is shown that every static-priority algorithm can miss deadlines although close to 50% of the capacity is requested. The new algorithms in this thesis have the following performance. In periodic scheduling, the capacity that can be requested without missing a deadline is: 33% for migrative scheduling and 50% for non-migrative scheduling. In aperiodic scheduling, many performance metrics have been used in previous research. With the aperiodic model used in this thesis, the new algorithms in this thesis have the following performance. The capacity that can be requested without missing a deadline is: 50% for migrative scheduling and 31% for non-migrative scheduling.
BibTeX:
@phdthesis{Andersson2003,
  author = {Andersson, Björn},
  title = {Static--priority scheduling on multiprocessors},
  school = {Chalmers University of Technology},
  year = {2003},
  url = {papers/Andersson2003.pdf}
}
Andersson, B., Baruah, S.K. and Jonsson, J. Static--priority scheduling on multiprocessors 2001 Proceedings of the 22nd IEEE Real--Time Systems Symposium (RTSS), pp. 193-202  inproceedings DOI URL 
Abstract: The preemptive scheduling of systems of periodic tasks on a platform comprised of several identical processors is considered. A scheduling algorithm is proposed for static--priority scheduling of such systems; this algorithm is a simple extension of the uniprocessor rate-monotonic scheduling algorithm. It is proven that this algorithm successfully schedules any periodic task system with a worst-case utilization no more than a third the capacity of the multiprocessor platform. It is also shown that no static-priority multiprocessor scheduling algorithm (partitioned or global) can guarantee schedulability for a periodic task set with a utilization higher than one half the capacity of the multiprocessor platform.
BibTeX:
@inproceedings{Andersson2001,
  author = {Andersson, Björn and Baruah, Sanjoy K. and Jonsson, Jan},
  title = {Static--priority scheduling on multiprocessors},
  booktitle = {Proceedings of the 22nd IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2001},
  pages = {193--202},
  url = {papers/Andersson2001.pdf},
  doi = {http://doi.org/10.1109/REAL.2001.990610}
}
Andersson, B., Baruah, S.K. and Jonsson, J. Static--priority scheduling on multiprocessors 2001 (TR01-016)School: University of North Carolina  techreport URL 
Abstract: The preemptive scheduling of systems of periodic tasks on a platform comprised of several identical multiprocessors is considered. A scheduling algorithm is proposed for static--priority scheduling of such systems; this algorithm is a simple extension of the uniprocessor rate-monotonic scheduling algorithm. It is proven that this algorithm successfully schedules any periodic task system with a worst-case utilization no more than a third the capacity of the multiprocessor platform; for the special case of harmonic periodic task systems, the algorithm is proven to successfully schedule any system with a worst-case utilization of no more than half the platform capacity.
BibTeX:
@techreport{Andersson2001a,
  author = {Andersson, Björn and Baruah, Sanjoy K. and Jonsson, Jan},
  title = {Static--priority scheduling on multiprocessors},
  school = {University of North Carolina},
  year = {2001},
  number = {TR01--016},
  url = {papers/Andersson2001a.pdf}
}
Andersson, B. and Bletsas, K. Sporadic Multiprocessor Scheduling with Few Preemptions 2008 (HURRAY-TR-080402)School: Polytechnic Institute of Porto (ISEP--IPP)  techreport URL 
Abstract: Consider the problem of scheduling n sporadic tasks so as to meet deadlines on m identical processors. A task is characterised by its minimum interarrival time and its worst--case execution time. Tasks are preemptible and may migrate between processors. We propose an algorithm with limited migration, configurable for a utilisation bound of 88% with few preemptions (and arbitrarily close to 100% with more preemptions).
BibTeX:
@techreport{Andersson2008,
  author = {Andersson, Björn and Bletsas, Konstantinos},
  title = {Sporadic Multiprocessor Scheduling with Few Preemptions},
  school = {Polytechnic Institute of Porto (ISEP--IPP)},
  year = {2008},
  number = {HURRAY--TR-080402},
  url = {papers/Andersson2008.pdf}
}
Andersson, B., Bletsas, K. and Baruah, S.K. Scheduling Arbitrary--Deadline Sporadic Task Systems on Multiprocessors 2008 Proceedings of the 29th IEEE Real--Time Systems Symposium (RTSS), pp. 385-394  inproceedings DOI URL 
Abstract: A new algorithm is proposed for scheduling preemptible arbitrary--deadline sporadic task systems upon multiprocessor platforms, with interprocessor migration permitted. This algorithm is based on a task-splitting approach - while most tasks are entirely assigned to specific processors, a few tasks (fewer than the number of processors) may be split across two processors. This algorithm can be used for two distinct purposes: for actually scheduling specific sporadic task systems, and for feasibility analysis. Simulation- based evaluation indicates that this algorithm offers a significant improvement on the ability to schedule arbitrary- deadline sporadic task systems as compared to the contemporary state-of-art. With regard to feasibility analysis, the new algorithm is proved to offer superior performance guarantees in comparison to prior feasibility tests.
BibTeX:
@inproceedings{Andersson2008a,
  author = {Andersson, Björn and Bletsas, Konstantinos and Baruah, Sanjoy K.},
  title = {Scheduling Arbitrary--Deadline Sporadic Task Systems on Multiprocessors},
  booktitle = {Proceedings of the 29th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {385--394},
  url = {papers/Andersson2008a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2008.44}
}
Andersson, B. and Ekelin, C. Exact admission--control for integrated aperiodic and periodic tasks 2007 Journal of Computer and System Sciences
Vol. 73(2), pp. 225-241 
article DOI URL 
BibTeX:
@article{Andersson2007,
  author = {Andersson, Björn and Ekelin, Cecilia},
  title = {Exact admission--control for integrated aperiodic and periodic tasks},
  journal = {Journal of Computer and System Sciences},
  year = {2007},
  volume = {73},
  number = {2},
  pages = {225--241},
  url = {papers/Andersson2007.pdf},
  doi = {http://doi.org/10.1016/j.jcss.2006.04.001}
}
Andersson, B. and Jonsson, J. The utilization bounds of partitioned and pfair static--priority scheduling on multiprocessors are 50\% 2003 Proceedings of the 15th Euromicro Conference on Real--time Systems (ECRTS), pp. 33-40  inproceedings DOI URL 
Abstract: This paper studies preemptive static--priority scheduling on multiprocessors. We consider two approaches: global pfair static-priority scheduling and partitioned traditional static priority scheduling. We prove that if presented algorithms are used and if less than 50% of the capacity is used then all deadlines are met. It is known that no static-priority multiprocessor scheduling algorithm can achieve a utilization bound greater than 50%.
BibTeX:
@inproceedings{Andersson2003a,
  author = {Andersson, Björn and Jonsson, Jan},
  title = {The utilization bounds of partitioned and pfair static--priority scheduling on multiprocessors are 50\%},
  booktitle = {Proceedings of the 15th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2003},
  pages = {33--40},
  url = {papers/Andersson2003a.pdf},
  doi = {http://doi.org/10.1109/EMRTS.2003.1212725}
}
Andersson, B. and Jonsson, J. Preemptive Multiprocessor Scheduling Anomalies 2002 Proceedings of the 16th International Parallel and Distributed Processing Symposium (IPDPS), pp. 12-19  inproceedings DOI URL 
Abstract: Preemptive scheduling of periodically arriving tasks on a multiprocessor is considered. We show that many common multiprocessor real--time scheduling algorithms suffer from scheduling anomalies, that is, deadlines are originally met, but a decrease in execution times or an increase in periods of tasks can cause deadlines to be missed. We propose a partitioned multiprocessor fixed-priority scheduling algorithm with the prominent features that (i) it does not suffer from such scheduling anomalies and (ii) if less than 41% of the capacity is used then deadlines are met.
BibTeX:
@inproceedings{Andersson2002,
  author = {Andersson, Björn and Jonsson, Jan},
  title = {Preemptive Multiprocessor Scheduling Anomalies},
  booktitle = {Proceedings of the 16th International Parallel and Distributed Processing Symposium (IPDPS)},
  publisher = {IEEE Computer Society},
  year = {2002},
  pages = {12--19},
  url = {papers/Andersson2002.pdf},
  doi = {http://doi.org/10.1109/IPDPS.2002.1015483}
}
Andersson, B. and Tovar, E. Multiprocessor Scheduling with Few Preemptions 2006 Proceedings of the 12th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 322-334  inproceedings DOI URL 
Abstract: Consider the problem of scheduling a set of periodically arriving tasks on a multiprocessor with the goal of meeting deadlines. Processors are identical and have the same speed. Tasks can be preempted and they can migrate between processors. We propose an algorithm with a utilization bound of 66% and with few preemptions. It can trade a higher utilization bound for more preemptions and in doing so it has a utilization bound of 100%.
BibTeX:
@inproceedings{Andersson2006,
  author = {Andersson, Björn and Tovar, Eduardo},
  title = {Multiprocessor Scheduling with Few Preemptions},
  booktitle = {Proceedings of the 12th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {322--334},
  url = {papers/Andersson2006.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2006.45}
}
Årzén, K.-E., Cervin, A., Eker, J. and Sha, L. An Introduction to Control and Scheduling Co--Design 2000
Vol. 5Proceedings of the 39th IEEE Conference on Decision and Control (CDC), pp. 4865-4870 
inproceedings DOI URL 
Abstract: The paper presents the emerging field of integrated control and CPU--time scheduling, where more general scheduling models and methods that better suit the needs of control systems are developed. This creates possibilities for dynamic and flexible integrated control and scheduling frameworks, where the control design methodology takes the availability of computing resources into account during design and allows on-line trade-offs between control performance and computing resource utilization.
BibTeX:
@inproceedings{Aarzen2000,
  author = {Årzén, Karl--Erik and Cervin, Anton and Eker, Johan and Sha, Liu},
  title = {An Introduction to Control and Scheduling Co--Design},
  booktitle = {Proceedings of the 39th IEEE Conference on Decision and Control (CDC)},
  year = {2000},
  volume = {5},
  pages = {4865--4870},
  url = {papers/Aarzen2000.pdf},
  doi = {http://doi.org/10.1109/CDC.2001.914701}
}
Audsley, N.C. On priority assignment in fixed priority scheduling 2001 Information Processing Letters
Vol. 79(1), pp. 39-44 
article DOI URL 
BibTeX:
@article{Audsley2001,
  author = {Audsley, Neil C.},
  title = {On priority assignment in fixed priority scheduling},
  journal = {Information Processing Letters},
  year = {2001},
  volume = {79},
  number = {1},
  pages = {39--44},
  url = {papers/Audsley2001.pdf},
  doi = {http://doi.org/10.1016/S0020--0190(00)00165-4}
}
Audsley, N.C. Optimal Priority Assignment and Feasibility of Static Priority Tasks with Arbitrary Start Times 1991 (YCS 164)School: University of York, Department of Computer Science  techreport URL 
Abstract: Within the hard real--time community, static priority pre-emptive scheduling is receiving increased attention. Current optimal priority assignment schemes require that at some point in the system lifetime all the tasks must be released simultaneously. Two main optimal priority assignment schemes have been proposed: rate-monotonic, where task period equals deadline, and deadline-monotonic where task deadline maybe less than period. When tasks are permitted to have arbitrary start times, a common release time between all tasks in a task set may not occur. In this eventuality, both rate-monotonic and deadline-monotonic priority assignment cease to be optimal. This paper presents a method of determining if the tasks with arbitrary release times will ever share a common release time. This has complexity O(m ln m) in the longest task period. Also, an optimal priority assignment method is given, of complexity O(n² + n) in the number of tasks. Finally, an efficient feasibility test is presented, for those task sets whose tasks do not share a common release time.
BibTeX:
@techreport{Audsley1991,
  author = {Audsley, Neil C.},
  title = {Optimal Priority Assignment and Feasibility of Static Priority Tasks with Arbitrary Start Times},
  school = {University of York, Department of Computer Science},
  year = {1991},
  number = {YCS 164},
  url = {papers/Audsley1991.pdf}
}
Audsley, N.C. Deadline Monotonic Scheduling 1990 (YCS-146)School: University of York, Department of Computer Science  techreport  
Abstract: This paper investigates schedulability tests for mixtures of periodic and aperiodic processes. Following an introduction outlining the constraints associated with rate-monotonic scheduling new schedulability tests are presented for deadline-monotonic scheduling. These apply to collections of periodic processes which have periods not necessarily equal to their deadlines (as is the case for rate-monotonic scheduling). The introduction of aperiodic (sporadic) processes can be catered for in the rate-monotonic scheme by the use of sporadic servers. Restrictions on this method are investigated and a new model based on deadline-monotonic scheduling is described. This model has the property that any mixture of sporadic and periodic process deadlines can be guaranteed (subject to passing an appropriate schedulability test)
BibTeX:
@techreport{Audsley1990,
  author = {Audsley, Neil C.},
  title = {Deadline Monotonic Scheduling},
  school = {University of York, Department of Computer Science},
  year = {1990},
  number = {YCS-146}
}
Audsley, N.C., Alan, B., Tindell, K.W. and Wellings, A.J. Applying new scheduling theory to static priority pre--emptive scheduling 1993 Software Engineering Journal
Vol. 8(5), pp. 284-292 
article URL 
Abstract: The paper presents exact schedulability analyses for real--time systems scheduled at runtime with a static priority pre-emptive dispatcher. The tasks to be scheduled are allowed to experience internal blocking (from other tasks with which they share resources) and (with certain restrictions) to release jitter, such as waiting for a message to arrive. The analysis presented is more general than that previously published and subsumes, for example, techniques based on the rate monotonic approach. In addition to presenting the relevant theory, an existing avionics case study is described and analysed. The predictions that follow from this analysis are seen to be in close agreement with the behaviour exhibited during simulation studies.
BibTeX:
@article{Audsley1993,
  author = {Audsley, Neil C. and Burns Alan and Tindell, Ken W. and Wellings, Andy J.},
  title = {Applying new scheduling theory to static priority pre--emptive scheduling},
  journal = {Software Engineering Journal},
  year = {1993},
  volume = {8},
  number = {5},
  pages = {284--292},
  url = {papers/Audsley1993.pdf}
}
Aupy, G., Benoit, A., Dufossé, F. and Robert, Y. Reclaiming the energy of a schedule: models and algorithms 2012 Concurrency and Computation: Practice and Experience  article DOI  
Abstract: We consider a task graph to be executed on a set of processors. We assume that the mapping is given, say by an ordered list of tasks to execute on each processor, and we aim at optimizing the energy consumption while enforcing a prescribed bound on the execution time. Although it is not possible to change the allocation of a task, it is possible to change its speed. Rather than using a local approach such as backfilling, we consider the problem as a whole and study the impact of several speed variation models on its complexity. For continuous speeds, we give a closed--form formula for trees and series–parallel graphs, and we cast the problem into a geometric programming problem for general directed acyclic graphs. We show that the classical dynamic voltage and frequency scaling (DVFS) model with discrete modes leads to an NP-complete problem, even if the modes are regularly distributed (an important particular case in practice, which we analyze as the incremental model). On the contrary, the Vdd-hopping model that allows to switch between different supply voltages (VDD) while executing a task leads to a polynomial solution. Finally, we provide an approximation algorithm for the incremental model, which we extend for the general DVFS model.
BibTeX:
@article{Aupy2012,
  author = {Aupy, Guillaume and Benoit, Anne and Dufossé, Fanny and Robert, Yves},
  title = {Reclaiming the energy of a schedule: models and algorithms},
  journal = {Concurrency and Computation: Practice and Experience},
  year = {2012},
  doi = {http://doi.org/10.1002/cpe.2889}
}
Aussaguès, C. Placement Optimal de Tâches pour les Systèmes Parallèles Temps--Réel Critiques 1998 School: Université de la Méditerrannée Aix--Marseille II  phdthesis  
Abstract: Cette thèse traite de la conception correcte des systèmes parallèles temps critiques. Ils constituent une composante essentielle des systèmes informatiques de hautes performances de contrôle--commande que l'on trouve par exemple dans le nucléaire et plus généralement dans les systèmes parallèles enfouis. La vérification des propriétés de correction temporelle de ces systèmes est au cœur des travaux de cette thèse. Notre contribution peut se caractériser en trois points : l'analyse et l'extension d'un modèle de programmation associé à cette classe de systèmes la proposition d'une méthode de résolution originale fondée sur un nouvel opérateur de produit synchronisé la validation de cette approche par son implémentation et évaluation Les travaux présentés concernent en particulier le problème majeur du placement optimal des processus parallèles suivant des stratégies respectant en priorité les contraintes temporelles imposées, i.e. respectant la ponctualité. La recherche des critères d'optimalité comporte également des paramètres spécifiques lorsqu'on veut dimensionner l'architecture cible en tenant compte de contraintes opérationnelles. Notre approche repose sur l'analyse de la faisabilité, avant exécution, de l'ordonnancement dynamique des tâches guidé par les échéances, supposé exister sur chaque processeur. Cela a conduit à définir l'opérateur de produit synchronisé des graphes d'état des tâches pour caractériser leur exécution simultanée. A partir du graphe du produit synchronisé est engendré automatiquement un système de contraintes permettant de calculer une charge maximale des tâches sur un processeur et de vérifier analytiquement la ponctualité. Les communications, la vérification de leur ponctualité et leur intégration au problème de placement constituent la deuxième contribution de cette thèse. Enfin, l'algorithme de résolution global intégrant l'allocation des tâches et des communications a été mis en œuvre et évalué dans le cadre du projet OASIS du CEA/Saclay.
BibTeX:
@phdthesis{Aussagues1998a,
  author = {Aussaguès, Christophe},
  title = {Placement Optimal de Tâches pour les Systèmes Parallèles Temps--Réel Critiques},
  school = {Université de la Méditerrannée Aix--Marseille II},
  year = {1998}
}
Aussaguès, C. and David, V. A Method and a Technique to Model and Ensure Timeliness in Safety Critical Real--Time Systems 1998 Proceedings of the 4th IEEE International Conference on Engineering of Complex Computer Systems (ICECCS), pp. 2-12  inproceedings DOI URL 
Abstract: The main focus of this paper is the problem of ensuring timeliness in safety critical systems. First, we introduce a method and its associated technique to model both real--time tasks and the timeliness ensuring concern when tasks are executed in parallel. This approach is based on formal aspects of our real-time tasks model and on the definition of the synchronized product operator on the tasks. Real-time tasks are equivalent to their state-transition diagrams and the operator allows us to compose the diagrams of a set of tasks to represent their interactions. The operator is then used to map the tasks to a system of linear constraints to determine the schedulability of the tasks and deduce a system load upper bound. An illustration of our technique on a safety critical study case is presented in which the timeliness property can be achieved for the real-time set of tasks executed in parallel on the same processor. We also introduce how this work can be applied to the multiprocessor case.
BibTeX:
@inproceedings{Aussagues1998,
  author = {Aussaguès, Christophe and David, Vincent},
  title = {A Method and a Technique to Model and Ensure Timeliness in Safety Critical Real--Time Systems},
  booktitle = {Proceedings of the 4th IEEE International Conference on Engineering of Complex Computer Systems (ICECCS)},
  publisher = {IEEE Computer Society},
  year = {1998},
  pages = {2--12},
  url = {papers/Aussagues1998.pdf},
  doi = {http://doi.org/10.1109/ICECCS.1998.706651}
}
Aussaguès, C., Ohayon, E., Brifault, K. and Dinh, Q.-T. Using Multi--Core Architectures to Execute High Performance-Oriented Real-Time Applications 2009 Proceedings of the International Conference on Parallel Computing (ParCo), pp. 8  inproceedings URL 
Abstract: This paper presents a method and the associated tools to design and implement embedded real--time systems that execute high-performance-oriented applications on multi-core architectures. After presenting the OASIS design, compilation and execution framework, the paper focuses on the principles of the modifications performed on the safety-oriented real-time kernel to execute transparently and consistently multitasking applications on multi-cores. It then gives the first results of benchmarking performed on a Dassault Aviation’s HPC application called “2D-tracking algorithm”. It concludes on the future works towards the introduction of data-parallelism in the OASIS parallel time-triggered programming and underlying execution models.
BibTeX:
@inproceedings{Aussagues2009,
  author = {Aussaguès, Christophe and Ohayon, Emmanuel and Brifault, Karine and Dinh, Quang--Thang},
  title = {Using Multi--Core Architectures to Execute High Performance-Oriented Real-Time Applications},
  booktitle = {Proceedings of the International Conference on Parallel Computing (ParCo)},
  year = {2009},
  pages = {8},
  url = {papers/Aussagues2009.pdf}
}
Austad, H. and Hendseth, S. A Survey of Real--Time Scheduling algorithms for the Linux kernel 2008 (TTK4540)School: Norwegian University of Science and Technology  techreport URL 
BibTeX:
@techreport{Austad2008,
  author = {Austad, Henrik and Hendseth, Sverre},
  title = {A Survey of Real--Time Scheduling algorithms for the Linux kernel},
  school = {Norwegian University of Science and Technology},
  year = {2008},
  number = {TTK4540},
  url = {papers/Austad2008.pdf}
}
Aydin, H. and Yang, Q. Energy--Aware Partitioning for Multiprocessor Real-Time Systems 2003 Proceedings of the 17th International Parallel and Distributed Processing Symposium (IPDPS), pp. 9pp  inproceedings DOI URL 
Abstract: In this paper, we address the problem of partitioning periodic real--time tasks in a multiprocessor platform by considering both feasibility and energy-awareness perspectives: our objective is to compute the feasible partitioning that results in minimum energy consumption on multiple identical processors by using variable voltage Earliest-Deadline-First scheduling. We show that the problem is NP-Hard in the strong sense on m >= 2 processors even when feasibility is guaranteed a priori. Then, we develop our framework where load balancing plays a major role in producing energy-efficient partitionings. We evaluate the feasibility and energy-efficiency performances of partitioning heuristics experimentally.
BibTeX:
@inproceedings{Aydin2003,
  author = {Aydin, Hakan and Yang, Qi},
  title = {Energy--Aware Partitioning for Multiprocessor Real-Time Systems},
  booktitle = {Proceedings of the 17th International Parallel and Distributed Processing Symposium (IPDPS)},
  publisher = {IEEE Computer Society},
  year = {2003},
  pages = {9pp},
  url = {papers/Aydin2003.pdf},
  doi = {http://doi.org/10.1109/IPDPS.2003.1213225}
}
Ayed, H., Mifdaoui, A. and Fraboul, C. Gateway Optimization for an Heterogeneous avionics network AFDX--CAN 2011 Proceedings of the Work--in-Progress Session of the 32nd IEEE Real-Time Systems Symposium (WiP RTSS)  inproceedings URL 
Abstract: The gateway impact on the end to end system performances is a major challenge in the design process of heterogeneous embedded systems. In this paper, this problem is tackled for a specific avionics network AFDX with CAN to identify the main interconnection issues. The results herein show the possible enhancements of the system performances thanks to an optimized gateway based on a frames pooling strategy, compared to a basic gateway.
BibTeX:
@inproceedings{Ayed2011,
  author = {Ayed, Hamdi and Mifdaoui, Ahlem and Fraboul, Christian},
  title = {Gateway Optimization for an Heterogeneous avionics network AFDX--CAN},
  booktitle = {Proceedings of the Work--in-Progress Session of the 32nd IEEE Real-Time Systems Symposium (WiP RTSS)},
  publisher = {IEEE Computer Society},
  year = {2011},
  url = {papers/Ayed2011.pdf}
}
Aysan, H. and Punnekkat, S. A Generalised Error Model and Schedulability Guarantees for Dependable Real--Time Systems 2011 Proceedings of the 1st International Workshop on Dependable and Secure Industrial and Embedded Systems (WORDS), pp. 8pp  inproceedings URL 
Abstract: The fundamental requirement for the design of effective and efficient fault--tolerance mechanisms in dependable real-time systems is a realistic and applicable model of potential faults, their manifestations and consequences. Fault and error models also need to be evolved based on the changes in the environments of usage or even based on technological advances. In this paper we propose a novel probabilistic burst error model in lieu of the commonly used simplistic fault assumptions. We introduce an approach to reason about real-time systems schedulability under the proposed error model in a probabilistic manner. We first present a sufficient analysis that accounts for the worst case interference caused by error bursts on the response times of tasks scheduled under the fixed priority scheduling (FPS) policy. Further, we identify potential sources of pessimism in the calculations and propose an algorithm that refines the results.
BibTeX:
@inproceedings{Aysan2011,
  author = {Aysan, Hüseyin and Punnekkat, Sasikumar},
  title = {A Generalised Error Model and Schedulability Guarantees for Dependable Real--Time Systems},
  booktitle = {Proceedings of the 1st International Workshop on Dependable and Secure Industrial and Embedded Systems (WORDS)},
  year = {2011},
  pages = {8pp},
  url = {papers/Aysan2011.pdf}
}
Bado, B., George, L., Courbin, P. and Goossens, J. A semi--partitioned approach for parallel real-time scheduling 2012 Proceedings of the 20th International Conference on Real--Time and Network Systems (RTNS), pp. 151-160  inproceedings DOI URL 
Abstract: In this paper, we consider the problem of scheduling periodic Multi--Phase Multi-Thread tasks on a set of m identical processors with Earliest Deadline First (EDF) scheduling. Each periodic task is defined by a sequence of phases with offsets that can be possibly parallelized. We use a portioned semi-partitioned approach with migrations at local deadlines assigned to each phase. We extend this approach to take into account phase parallelism. The phase parallelism we consider is an extension of the popular job parallelism. A phase, if parallelizable, can be decomposed into parallel threads run on a configurable number of processors. We only require simultaneous execution of threads inside a window equal to the local deadline of their associated phase. To decide on the schedulability of a Multi-Phase Multi-Thread task, we extend the popular uniprocessor EDF feasibility condition for periodic asynchronous tasks. We propose two new schedulability tests for EDF that significantly improve the well known Leung and Merill feasibility test based on the feasibility interval [Omin, Omax + 2P], where Omin and Omax are respectively the minimum and maximum phase offsets and P the least common multiple of the task periods. The first schedulability test is used when an EDF simulation is needed and gives, by simulation, a 44% gain in simulation speed. The second method provides a sufficient schedulability test with a time interval of length P based on the demand bound function. Finally, we study three local deadline assignment heuristics assigned to parallelizable phases. We compare and analyze the performances obtained by simulation for those three local deadline assignment heuristics.
BibTeX:
@inproceedings{Bado2012,
  author = {Bado, Benjamin and George, Laurent and Courbin, Pierre and Goossens, Joël},
  title = {A semi--partitioned approach for parallel real-time scheduling},
  booktitle = {Proceedings of the 20th International Conference on Real--Time and Network Systems (RTNS)},
  publisher = {ACM},
  year = {2012},
  pages = {151--160},
  url = {papers/Bado2012.pdf},
  doi = {http://doi.org/10.1145/2392987.2393006}
}
Bak, S., Caccamo, M. and Sha, L. Real--Time Reachability for Verified Simplex Design 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 138-148  inproceedings DOI URL 
Abstract: The Simplex Architecture ensures the safe use of an unverifiable complex controller by using a verified safety controller and verified switching logic. This architecture enables the safe use of high--performance, untrusted, and complex control algorithms without requiring them to be formally verified. Simplex incorporates a supervisory controller and safety controller that will take over control if the unverified logic misbehaves. The supervisory controller should (1) guarantee the system never enters and unsafe state (safety), but (2) use the complex controller as much as possible (minimize conservatism).
The problem of precisely and correctly defining this switching logic has previously been considered either using a control--theoretic optimization approach, or through an offline hybrid systems reachability computation. In this work, we prove that a combined online/offline approach, which uses aspects of the two earlier methods along with a real-time reachability computation, also maintains safety, but with significantly less conservatism. We demonstrate the advantages of this unified approach on a saturated inverted pendulum system, where the usable region of attraction is 227% larger than the earlier approach.
BibTeX:
@inproceedings{Bak2014,
  author = {Bak, Stanley and Caccamo, Marco and Sha, Lui},
  title = {Real--Time Reachability for Verified Simplex Design},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {138--148},
  url = {papers/Bak2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.21}
}
Baker, T.P. An Analysis of Fixed--Priority Schedulability on a Multiprocessor 2006 Real--Time Systems
Vol. 32(1-2), pp. 49-71 
article DOI URL 
Abstract: A new feasibility test for preemptive scheduling of periodic or sporadic real--time tasks on a single-queue m-server system allows for arbitrary fixed task priorities and arbitrary deadlines. For the special case when deadline equals period and priorities are rate monotonic, any set of tasks with maximum individual task utilization umax and minimum individual task utilization umin is feasible if the total utilization does not exceed m(1 − umax)/2 + umin.
BibTeX:
@article{Baker2006,
  author = {Baker, Theodore P.},
  title = {An Analysis of Fixed--Priority Schedulability on a Multiprocessor},
  journal = {Real--Time Systems},
  year = {2006},
  volume = {32},
  number = {1--2},
  pages = {49--71},
  url = {papers/Baker2006.pdf},
  doi = {http://doi.org/10.1007/S11241--005-4686-1}
}
Baker, T.P. Comparison of Empirical Success Rates of Global vs. Partitioned Fixed--Priority and EDF Scheduling for Hard Real Time 2005 (TR-050601)School: Florida State University  techreport URL 
Abstract: Improvements in schedulability tests for global fixed--priority and EDF scheduling in a homogeneous multiprocessor (symmetric multiprocessing) environment have shown that the worst-case guaranteed achievable utilization levels for global EDF scheduling equals what can be achieved with partitioned scheduling, and both ways of applying EDF scheduling out-perform fixed-priority scheduling, for sets of independent periodic or sporadic hard-deadline tasks with deadline equal to period. However, less is known about the comparative performance of the partitioned vs. global and EDF vs. fixed-priority approaches in the average and without the restriction that deadline equal period, and particular which of the known combinations of a scheduling algorithm and a sufficient a priori test of schedulability is more likely to succeed in verifiably scheduling a set of tasks to meet all deadlines. This paper compares the performance of several such combinations on a variety of pseudo-randomly chosen sets of sporadic tasks.
BibTeX:
@techreport{Baker2005a,
  author = {Baker, Theodore P.},
  title = {Comparison of Empirical Success Rates of Global vs. Partitioned Fixed--Priority and EDF Scheduling for Hard Real Time},
  school = {Florida State University},
  year = {2005},
  number = {TR--050601},
  url = {papers/Baker2005a.pdf}
}
Baker, T.P. Multiprocessor EDF and Deadline Monotonic Schedulability Analysis 2003 Proceedings of the 24th IEEE Real--Time Systems Symposium (RTSS), pp. 120-129  inproceedings DOI URL 
Abstract: Schedulability tests are presented for preemptive earliest--deadline-first and deadline-monotonic scheduling of periodic or sporadic real-time tasks on a single-queue-server system, in which the deadline of a task may be less than or equal to the task period. These results subsume and generalize several known utilization-based multiprocessor schedulability tests, and are derived via an independent proof.
BibTeX:
@inproceedings{Baker2003,
  author = {Baker, Theodore P.},
  title = {Multiprocessor EDF and Deadline Monotonic Schedulability Analysis},
  booktitle = {Proceedings of the 24th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2003},
  pages = {120--129},
  url = {papers/Baker2003.pdf},
  doi = {http://doi.org/10.1109/REAL.2003.1253260}
}
Baker, T.P. Stack--Based Scheduling of Realtime Processes 1991 Real--Time Systems
Vol. 3(1), pp. 67-99 
article DOI URL 
Abstract: The Priority Ceiling Protocol (PCP) of Sha, Rajkumar and Lehoczky is a policy for locking binary semaphores that bounds priority inversion (i.e., the blocking of a job while a lower priority job executes), and thereby improves schedulability under fixed priority preemptive scheduling. We show how to extend the PCP to handle: multiunit resources, which subsume binary semaphores and reader--writer locks; dynamic priority schemes, such as earliest-deadline-first (EDF), that use static "preemption levels"; sharing of runtime stack space between jobs. These extensions can be applied independently, or together. The Stack Resource Policy (SRP) is a variant of the SRP that incorporates the three extensions mentioned above, plus the conservative assumption that each job may require the use of a shared stack. This avoids unnecessary context switches and allows the SRP to be implemented very simply using a stack. We prove a schedulability result for EDF scheduling with the SRP that is tighter than the one proved previously for EDF with a dynamic version of the PCP. The Minimal SRP (MSRP) is a slightly more complex variant of the SRP, which has similar properties, but imposes less blocking. The MSRP is optimal for stack sharing systems, in the sense that it is the least restrictive policy that strictly bounds priority inversion and prevents deadlock for rate monotone (RM) and earliest-deadline-first (EDF) scheduling.
BibTeX:
@article{Baker1991,
  author = {Baker, Theodore P.},
  title = {Stack--Based Scheduling of Realtime Processes},
  journal = {Real--Time Systems},
  year = {1991},
  volume = {3},
  number = {1},
  pages = {67--99},
  url = {papers/Baker1991.pdf},
  doi = {http://doi.org/10.1007/BF00365393}
}
Baker, T.P. A stack--based resource allocation policy for realtime processes 1990 Proceedings of the 11th IEEE Real--Time Systems Symposium (RTSS), pp. 191-200  inproceedings URL 
Abstract: The stack resource policy (SRP) is a resource allocation policy which permits processes with different priorities to share a single runtime stack. It is a refinement of the priority ceiling protocol (PCP), which strictly bounds priority inversion and permits simple schedulability tests. With or without stack sharing, the SRP offers the following improvements over the PCP: (1) it unifies the treatment of stack, reader--writer, multiunit resources, and binary semaphores; (2) it applies directly to some dynamic scheduling policies, including earliest deadline first (EDF), as well as to static priority policies; (3) with EDF scheduling, it supports a stronger schedulability test; and (4) it reduces the maximum number of context switches for a job execution request by a factor of two. It is at least as good as the PCP in reducing maximum priority inversion.
BibTeX:
@inproceedings{Baker1990,
  author = {Baker, Theodore P.},
  title = {A stack--based resource allocation policy for realtime processes},
  booktitle = {Proceedings of the 11th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1990},
  pages = {191--200},
  url = {papers/Baker1990.pdf}
}
Baker, T.P. and Baruah, S.K. An analysis of global EDF schedulability for arbitrary--deadline sporadic task systems 2009 Real--Time Systems
Vol. 43(1), pp. 3-24 
article DOI URL 
Abstract: Recent results on the global multiprocessor EDF scheduling of sporadic task systems are, for the most part, applicable only to task systems in which each task’s relative deadline parameter is constrained to be no larger than its minimum inter--arrival separation. This paper introduces new analysis techniques that allow for similar results to be derived for task systems in which individual tasks are not constrained in this manner. For tasks with deadlines greater than their minimum interarrival separation, two models are considered, with and without an implicit intratask job precedence constraint. The new analyses yield schedulability conditions that strictly dominate some previously proposed tests that are generally accepted to represent the current state of the art in multiprocessor EDF schedulability analysis, and permits the derivation of an improved speed-up bound.
BibTeX:
@article{Baker2009,
  author = {Baker, Theodore P. and Baruah, Sanjoy K.},
  title = {An analysis of global EDF schedulability for arbitrary--deadline sporadic task systems},
  journal = {Real--Time Systems},
  year = {2009},
  volume = {43},
  number = {1},
  pages = {3--24},
  url = {papers/Baker2009.pdf},
  doi = {http://doi.org/10.1007/s11241--009-9075-8}
}
Baker, T.P. and Baruah, S.K. Sustainable Multiprocessor Scheduling of Sporadic Task Systems 2009 Proceedings of the 21st Euromicro Conference on Real--time Systems (ECRTS), pp. 141-150  inproceedings DOI URL 
Abstract: A scheduling policy or a schedulability test is defined to be sustainable with respect to a particular workload model if any task system represented in that model that is determined to be schedulable remains so if it behaves "better" than mandated by its specifications. We investigate the sustainability properties of global scheduling algorithms when applied to systems represented using the sporadic task model. We show that Fixed--Priority (FP) scheduling of sporadic task sets is sustainable under a variety of scheduling parameter relaxations, including decreased execution requirements, later arrivals, and deadline relaxations. It follows that all sufficient tests of global FP schedulability are sustainable for sporadic task systems. We show that the Earliest Deadline First (EDF) and Earliest-Deadline with Zero Laxity scheduling policies are sustainable with respect to decreased execution requirements and later arrivals. We also introduce a notion of self-sustainability, and show that many widely-used EDF schedulability tests are not self-sustainable but one is.
BibTeX:
@inproceedings{Baker2009a,
  author = {Baker, Theodore P. and Baruah, Sanjoy K.},
  title = {Sustainable Multiprocessor Scheduling of Sporadic Task Systems},
  booktitle = {Proceedings of the 21st Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {141--150},
  url = {papers/Baker2009a.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2009.25}
}
Baker, T.P., Cirinei, M. and Bertogna, M. EDZL scheduling analysis 2008 Real--Time Systems
Vol. 40(3), pp. 264-289 
article DOI URL 
Abstract: A schedulability test is derived for the global Earliest Deadline Zero Laxity (EDZL) scheduling algorithm on a platform with multiple identical processors. The test is sufficient, but not necessary, to guarantee that a system of independent sporadic tasks with arbitrary deadlines will be successfully scheduled, with no missed deadlines, by the multiprocessor EDZL algorithm. Global EDZL is known to be at least as effective as global Earliest--Deadline-First (EDF) in scheduling task sets to meet deadlines. It is shown, by testing on large numbers of pseudo-randomly generated task sets, that the combination of EDZL and the new schedulability test is able to guarantee that far more task sets meet deadlines than the combination of EDF and known EDF schedulability tests. In the second part of the paper, an improved version of the EDZL-schedulability test is presented. This new algorithm is able to efficiently exploit information on the slack values of interfering tasks, to iteratively refine the estimation of the interference a task can be subjected to. This iterative algorithm is shown to have better performance than the initial test, in terms of schedulable task sets detected.
BibTeX:
@article{Baker2008,
  author = {Baker, Theodore P. and Cirinei, Michele and Bertogna, Marko},
  title = {EDZL scheduling analysis},
  journal = {Real--Time Systems},
  year = {2008},
  volume = {40},
  number = {3},
  pages = {264--289},
  url = {papers/Baker2008.pdf},
  doi = {http://doi.org/10.1007/s11241--008-9061-6}
}
Baker, T.P., Fisher, N.W. and Baruah, S.K. Algorithms for Determining the Load of a Sporadic Task System 2005 (TR-051201)School: Florida State University and The University of North Carolina at Chapel Hill  techreport URL 
Abstract: In this report, we discuss a metric that characterizes the load of a sporadic task system. We give an exact, exponential--time algorithm that determines a task system’s load by essentially simulating the execution of task system. In addition, we also give an algorithm that can determine the load of a task system within an arbitrarily small threshold > 0. While the worst-case time complexity of the approximation is still possibly exponential, we have empirically observed that this algorithm generally provides a very significant reduction in the time that we must simulate the task system to obtain the load. Additionally, we provide proofs of correctness for our algorithms.
BibTeX:
@techreport{Baker2005,
  author = {Baker, Theodore P. and Fisher, Nathan Wayne and Baruah, Sanjoy K.},
  title = {Algorithms for Determining the Load of a Sporadic Task System},
  school = {Florida State University and The University of North Carolina at Chapel Hill},
  year = {2005},
  number = {TR--051201},
  url = {papers/Baker2005.pdf}
}
Baldellon, O., Fabre, J.-C. and Roy, M. Distributed Monitoring of Temporal System Properties using Petri Nets 2012 Proceedings of the 31st IEEE Symposium on Reliable Distributed Systems (SRDS), pp. 398-399  inproceedings DOI URL 
Abstract: Supervising a system in operation allows to detect a violation of system specification or temporal properties, and is the first step required by any reconfiguration mechanism. In this work, we focus on run--time verification of temporal system properties in distributed and real-time systems. Based on a description of a property that includes events and temporal constraints, expressed as an arc timed Petri net, we automatically derive a monitoring system responsible for checking this property. The proposed approach enables the distributed verification of system properties. Our contribution is twofold. On the theoretical side, we introduce a slight modification of the semantics of Petri nets to be able to execute it in partial executions and noisy observation environments. On the practical side, we show how to use this formal framework to provide a distributed and efficient monitoring system, and describe its current implementation.
BibTeX:
@inproceedings{Baldellon2012,
  author = {Baldellon, Oliver and Fabre, Jean--Charles and Roy, Matthieu},
  title = {Distributed Monitoring of Temporal System Properties using Petri Nets},
  booktitle = {Proceedings of the 31st IEEE Symposium on Reliable Distributed Systems (SRDS)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {398--399},
  url = {papers/Baldellon2012.pdf},
  doi = {http://doi.org/10.1109/SRDS.2012.21}
}
Bao, X., Yu, G., Dai, J. and Zhu, X. Li-Fi: Light fidelity-a survey 2015 Wireless Networks
Vol. 21(6), pp. 1879-1889 
article DOI URL 
Abstract: Visible light communication (VLC), which uses a vast unregulated and free light spectrum, has emerged to be a viable solution to overcome the spectrum crisis of radio frequency. Light fidelity (Li-Fi) is an optical networked communication in the subset of VLC to offload the mobile data traffics which offers many advantages at indoor scenario. In this article, we survey the key technologies for realizing Li-Fi and present the sate-of-the-art on each aspect, such as: indoor optical wireless channel model, the VLC modulation techniques with user satisfaction, OFDM in VLC, optical MIMO, optical spatial modulation, multiple user access, resource allocation, interference management and hybrid Li-Fi schemes. Some challenges and future work that need to be solved in the area are also described.
BibTeX:
@article{Bao2015,
  author = {Bao, Xu and Yu, Guanding and Dai, Jisheng and Zhu, Xiaorong},
  title = {Li-Fi: Light fidelity-a survey},
  journal = {Wireless Networks},
  year = {2015},
  volume = {21},
  number = {6},
  pages = {1879--1889},
  url = {papers/Bao2015.pdf},
  doi = {http://doi.org/10.1007/s11276-015-0889-0}
}
Barham, P., Dragovic, B., Fraser, K., Hand, S., Harris, T., Ho, A., Neugebauer, R., Pratt, I. and Warfield, A. Xen and the Art of Virtualization 2003 SIGOPS Operating Systems Review
Vol. 37(5), pp. 164-177 
article DOI URL 
Abstract: Numerous systems have been designed which use virtualization to subdivide the ample resources of a modern computer. Some require specialized hardware, or cannot support commodity operating systems. Some target 100% binary compatibility at the expense of performance. Others sacrifice security or functionality for speed. Few offer resource isolation or performance guarantees; most provide only best-effort provisioning, risking denial of service.This paper presents Xen, an x86 virtual machine monitor which allows multiple commodity operating systems to share conventional hardware in a safe and resource managed fashion, but without sacrificing either performance or functionality. This is achieved by providing an idealized virtual machine abstraction to which operating systems such as Linux, BSD and Windows XP, can be ported with minimal effort.Our design is targeted at hosting up to 100 virtual machine instances simultaneously on a modern server. The virtualization approach taken by Xen is extremely efficient: we allow operating systems such as Linux and Windows XP to be hosted simultaneously for a negligible performance overhead --- at most a few percent compared with the unvirtualized case. We considerably outperform competing commercial and freely available solutions in a range of microbenchmarks and system-wide tests.
BibTeX:
@article{Barham2003,
  author = {Barham, Paul and Dragovic, Boris and Fraser, Keir and Hand, Steven and Harris, Tim and Ho, Alex and Neugebauer, Rolf and Pratt, Ian and Warfield, Andrew},
  title = {Xen and the Art of Virtualization},
  journal = {SIGOPS Operating Systems Review},
  publisher = {ACM},
  year = {2003},
  volume = {37},
  number = {5},
  pages = {164--177},
  url = {/papers/Barham2003.pdf},
  doi = {http://doi.org/10.1145/1165389.945462}
}
Bartolini, C., Bini, E. and Lipari, G. Slack--based Sensitivity Analysis for EDF 2008 Proceedings of the Work--in-Progress Session of the 14th IEEE Real-Time and Embedded Technology and Applications Symposium (WiP RTAS), pp. 4pp  inproceedings URL 
Abstract: Real--time systems are characterized by several nonfunctional properties which are used to describe the temporal behaviour. Traditional schedulability analysis allows to determine whether the timing requirements are going to be met or not. On the other hand sensitivity analysis is also capable to measure the admissible variation to the non-functional properties. This is extremely important in practice since the non-functional parameters are often determined with a large margin of uncertainty. The purpose of this paper is to lay a basis for the sensitivity analysis for EDF which is comprehensive of the three basic properties (computation times, deadlines and periods) using a common methodology.
BibTeX:
@inproceedings{Bartolini2008,
  author = {Bartolini, Cesare and Bini, Enrico and Lipari, Giuseppe},
  title = {Slack--based Sensitivity Analysis for EDF},
  booktitle = {Proceedings of the Work--in-Progress Session of the 14th IEEE Real-Time and Embedded Technology and Applications Symposium (WiP RTAS)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {4pp},
  url = {papers/Bartolini2008.pdf}
}
Bartols, F., Steinbach, T., Korf, F., Buth, B. and Schmidt, T.C. Real--time Ethernet Residual Bus Simulation: A Model-Based Testing Approach for the Next-Generation In-Car Network 2014 Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS), pp. 267-276  inproceedings DOI URL 
Abstract: The increasing complexity of automotive networks, their challenging timing constraints and their high bandwidth demands require new concepts for future in--car communication. Real-time Ethernet is meant to be a suitable candidate for the next-generation in-car interconnection. However, model-based testing capabilities must be available as well. Applications must be validated prior the first assembly, due to the distributed development process. Methods like residual bus simulation are of particular interest to allow for testing systems in early development stages by emulating unfinished or not available parts of the system.

In this paper, we present a methodology and a feasibility study of a residual bus simulation in automotive real--time Ethernet systems. The challenges of applying this testing method in real-time Ethernet based networks with parallel packet transmission are outlined and compared to today's automotive bus system simulation approaches. Furthermore, the combination of different model-based testing techniques, that are not used in state-of-the-art commercial tools, are applied for the validation of non-functional timing requirements. An extension to an existing abstract test case model is proposed, which allows modelling temporal attributes. It is simultaneously used as simulation model to drive the residual bus simulation. We demonstrate the approach's feasibility by implementing a prototype residual bus simulator for real-time Ethernet networks and applying it to an example application.

BibTeX:
@inproceedings{Bartols2014,
  author = {Bartols, Florian and Steinbach, Till and Korf, Franz and Buth, Bettina and Schmidt, Thomas C.},
  title = {Real--time Ethernet Residual Bus Simulation: A Model-Based Testing Approach for the Next-Generation In-Car Network},
  booktitle = {Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS)},
  publisher = {ACM Press},
  year = {2014},
  pages = {267--276},
  url = {papers/Bartols2014.pdf},
  doi = {http://doi.org/10.1145/2659787.2659800}
}
Baruah, S.K. Mixed criticality scheduling is highly intractable   unpublished URL 
Abstract: The mixed criticality real--time workload model, described in Section 1 below, arises in certain safety-critical application domains that may be subject to mandatory certification requirements by statutory organizations. We show here (Section 2) that it is NP-hard in the strong sense to determine whether it is possible to successfully schedule a given system specified in this model upon a fully preemptive uniprocessor platform, such that all certification constraints are satisfied.
BibTeX:
@unpublished{Baruah,
  author = {Baruah, Sanjoy K.},
  title = {Mixed criticality scheduling is highly intractable},
  url = {papers/Baruah.pdf}
}
Baruah, S.K. Semantics--preserving implementation of multirate mixed-criticality synchronous programs 2012 Proceeding of the 20th International Conference on Real--Time and Network Systems (RTNS), pp. 11-19  inproceedings DOI URL 
Abstract: Model--based design methodologies such as Simulink/ State-flow, that are based on the synchrony assumption, are widely used in many safety-critical application domains including avionics and automotive systems. The synchrony assumption asserts that actions (such as the execution of code) occur instantaneously. However, actual platforms obviously do not satisfy the synchrony assumption. This paper considers the problem of obtaining resource-efficient implementations of programs that are written under the synchrony assumption on actual platforms, such that these implementations execute in a manner that is semantically consistent with the execution sequences that would occur if the synchrony assumption were to hold.
BibTeX:
@inproceedings{Baruah2012,
  author = {Baruah, Sanjoy K.},
  title = {Semantics--preserving implementation of multirate mixed-criticality synchronous programs},
  booktitle = {Proceeding of the 20th International Conference on Real--Time and Network Systems (RTNS)},
  publisher = {ACM},
  year = {2012},
  pages = {11--19},
  url = {papers/Baruah2012.pdf},
  doi = {http://doi.org/10.1145/2392987.2392989}
}
Baruah, S.K. The Partitioned EDF Scheduling of Sporadic Task Systems 2011 Proceedings of the 32nd IEEE International Real--Time Systems Symposium (RTSS), pp. 116-125  inproceedings DOI URL 
Abstract: The partitioned scheduling of sporadic task systems on identical multiprocessors is considered. This is known to be intractable (NP--hard in the strong sense). A polynomial-time approximation scheme (PTAS) is proposed for sporadic task systems satisfying the additional constraint that for each of the three parameters -- worst-case execution time, relative deadline, and period -- that characterize sporadic tasks, the ratio of the largest value to the smallest value is bounded from above by a constant.
BibTeX:
@inproceedings{Baruah2011,
  author = {Baruah, Sanjoy K.},
  title = {The Partitioned EDF Scheduling of Sporadic Task Systems},
  booktitle = {Proceedings of the 32nd IEEE International Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2011},
  pages = {116--125},
  url = {papers/Baruah2011.pdf},
  doi = {http://doi.org/10.1109/RTSS.2011.18}
}
Baruah, S.K. Techniques for Multiprocessor Global Schedulability Analysis 2007 Proceedings of the 28th IEEE International Real--Time Systems Symposium (RTSS), pp. 119-128  inproceedings DOI URL 
Abstract: The scheduling of sporadic task systems upon multiprocessor platforms is considered, when inter--processor migration is permitted. It is known that current schedulability tests for such systems perform quite poorly when compared to schedulability tests for partitioned scheduling. Limitations of current tests are identified, which may be responsible for the unsatisfactory performance of these tests. A new test that overcomes some of these limitations is proposed and proved correct.
BibTeX:
@inproceedings{Baruah2007,
  author = {Baruah, Sanjoy K.},
  title = {Techniques for Multiprocessor Global Schedulability Analysis},
  booktitle = {Proceedings of the 28th IEEE International Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {119--128},
  url = {papers/Baruah2007.pdf},
  doi = {http://doi.org/10.1109/RTSS.2007.35}
}
Baruah, S.K. Resource sharing in EDF-scheduled systems: a closer look 2006 Proceedings of the 27th IEEE Real--Time Systems Symposium (RTSS), pp. 379-387  inproceedings DOI URL 
Abstract: Resource sharing in priority-based systems can give rise to priority-inversion and blocking, wherein a job's execution is delayed because a lower-priority job holds some resource that is needed for execution. The stack resource policy (SRP) can be used to reduce such blocking in EDF-scheduled systems. An efficient implementation of an algorithm is presented for determining whether systems scheduled in this manner are feasible. Some interesting properties of such systems are derived. The technique of reducing the duration of blocking by the replication of selected resources is explored: an algorithm is presented which determines the minimum amount of resource replication necessary to achieve specified blocking times.
BibTeX:
@inproceedings{Baruah2006a,
  author = {Baruah, Sanjoy K.},
  title = {Resource sharing in EDF-scheduled systems: a closer look},
  booktitle = {Proceedings of the 27th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {379--387},
  url = {papers/Baruah2006a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2006.41}
}
Baruah, S.K. Optimal Utilization Bounds for the Fixed--Priority Scheduling of Periodic Task Systems on Identical Multiprocessors 2004 IEEE Transactions on Computers
Vol. 53(6), pp. 781-784 
article DOI URL 
Abstract: In fixed--priority scheduling, the priority of a job, once assigned, may not change. A new fixed-priority algorthm for scheduling systems of periodic tasks upon identical multiprocessors is proposed. This algorithm has an achievable utilization of ðm þ 1Þ=2 upon m unit-capacity processors. It is proven that this algorithm is optimal from the perspective of achievable utilization in the sense that no fixed-priority algorithm for scheduling periodic task systems upon identical multiprocessors may have an achievable utilization greater than ðm þ 1Þ=2.
BibTeX:
@article{Baruah2004a,
  author = {Baruah, Sanjoy K.},
  title = {Optimal Utilization Bounds for the Fixed--Priority Scheduling of Periodic Task Systems on Identical Multiprocessors},
  journal = {IEEE Transactions on Computers},
  year = {2004},
  volume = {53},
  number = {6},
  pages = {781--784},
  url = {papers/Baruah2004a.pdf},
  doi = {http://doi.org/10.1109/TC.2004.16}
}
Baruah, S.K., Bonifaci, V., D'Angelo, G., Li, H., Marchetti-Spaccamela, A., Van Der Ster, S. and Stougie, L. The preemptive uniprocessor scheduling of mixed--criticality implicit-deadline sporadic task systems 2012 Proceedings of the Euromicro Conference on Real--Time Systems (ECRTS), pp. 145-154  inproceedings DOI URL 
Abstract: Systems in many safety--critical application domains are subject to certification requirements. For any given system, however, it may be the case that only a subset of its functionality is safety-critical and hence subject to certification; the rest of the functionality is non safety critical and does not need to be certified, or is certified to a lower level of assurance. An algorithm called EDF-VD (for Earliest Deadline First with Virtual Deadlines) is described for the scheduling of such mixed-criticality task systems. Analyses of EDF-VD significantly superior to previously-known ones are presented, based on metrics such as processor speedup factor (EDF-VD is proved to be optimal with respect to this metric) and utilization bounds.
BibTeX:
@inproceedings{Baruah2012a,
  author = {Baruah, Sanjoy K. and Bonifaci, Vincenzo and D'Angelo, Gianlorenzo and Li, Haohan and Marchetti--Spaccamela, Alberto and Van Der Ster, Suzanne and Stougie, Leen},
  title = {The preemptive uniprocessor scheduling of mixed--criticality implicit-deadline sporadic task systems},
  booktitle = {Proceedings of the Euromicro Conference on Real--Time Systems (ECRTS)},
  publisher = {IEEE Computer Society Press},
  year = {2012},
  pages = {145--154},
  url = {papers/Baruah2012a.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2012.42}
}
Baruah, S.K., Bonifaci, V., D’Angelo, G., Li Haohan Marchetti-Spaccamela, A., Megow, N. and Stougie, L. Scheduling real--time mixed-criticality jobs 2010 Mathematical Foundations of Computer Science
Vol. 6281, pp. 90-101 
article DOI URL 
Abstract: Many safety--critical embedded systems are subject to certification requirements; some systems may be required to meet multiple sets of certification requirements, from different certification authorities. Certification requirements in such “mixed-criticality” systems give rise to interesting scheduling problems, that cannot be satisfactorily addressed using techniques from conventional scheduling theory. In this paper, we study a formal model for representing such mixed-criticality workloads. We demonstrate first the intractability of determining whether a system specified in this model can be scheduled to meet all its certification requirements, even for systems subject to two sets of certification requirements. Then we quantify, via the metric of processor speedup factor, the effectiveness of two techniques, reservation-based scheduling and priority-based scheduling, that are widely used in scheduling such mixed-criticality systems, showing that the latter of the two is superior to the former. We also show that the speedup factors are tight for these two techniques.
BibTeX:
@article{Baruah2010a,
  author = {Baruah, Sanjoy K. and Bonifaci, Vincenzo and D’Angelo, Gianlorenzo and Li, Haohan Marchetti--Spaccamela, Alberto and Megow, Nicole and Stougie, Leen},
  title = {Scheduling real--time mixed-criticality jobs},
  journal = {Mathematical Foundations of Computer Science},
  year = {2010},
  volume = {6281},
  pages = {90--101},
  url = {papers/Baruah2010a.pdf},
  doi = {http://doi.org/10.1007/978--3-642-15155-2_10}
}
Baruah, S.K., Bonifaci, V., Gianlorenzo, D., Marchetti-Spaccamela, A., Van Der Ster, S. and Stougie, L. Mixed--Criticality Scheduling of Sporadic Task Systems 2011 Proceedings of the 19th Annual European Symposium on Algorithms (ESA), pp. 555-566  inproceedings URL 
Abstract: We consider the scheduling of mixed--criticality task systems, that is, systems where each task to be scheduled has multiple levels of worst-case execution time estimates. We design a scheduling algorithm, EDF-VD, whose effectiveness we analyze using the processor speedup metric: we show that any 2-level task system that is schedulable on a unit-speed processor is correctly scheduled by EDF-VD using speed φ; here φ < 1.619 is the golden ratio. We also show how to generalize the algorithm to K > 2 criticality levels.We finally consider 2-level instances on m identical machines. We prove speedup bounds for scheduling an independent collection of jobs and for the partitioned scheduling of a 2-level task system.
BibTeX:
@inproceedings{Baruah2011b,
  author = {Baruah, Sanjoy K. and Bonifaci, Vincenzo and D'Angelo Gianlorenzo and Marchetti--Spaccamela, Alberto and Van Der Ster, Suzanne and Stougie, Leen},
  title = {Mixed--Criticality Scheduling of Sporadic Task Systems},
  booktitle = {Proceedings of the 19th Annual European Symposium on Algorithms (ESA)},
  publisher = {Springer--Verlag},
  year = {2011},
  pages = {555--566},
  url = {papers/Baruah2011b.pdf}
}
Baruah, S.K., Bonifaci, V., Marchetti-Spaccamela, A. and Stiller, S. Improved multiprocessor global schedulability analysis 2010 Real--Time Systems
Vol. 46(1), pp. 3-24 
article DOI URL 
Abstract: A new technique was recently introduced by Bonifaci et al. for the analysis of real--time systems scheduled on multiprocessor platforms by the global Earliest Deadline First (EDF) scheduling algorithm. In this paper, this technique is generalized so that it is applicable to the schedulability analysis of real-time systems scheduled on multiprocessor platforms by any work-conserving algorithm. The resulting analysis technique is applied to obtain a new sufficient global Deadline Monotonic (DM) schedulability test. It is shown that this new test is quantitatively superior to pre-existing DM schedulability analysis tests; in addition, the degree of its deviation from any hypothetical optimal scheduler (that may be clairvoyant) is quantitatively bounded. A new global EDF schedulability test is also proposed here that builds on the results of Bonifaci et al. This new test is shown to be less pessimistic and more widely applicable than the earlier result was, while retaining the strong theoretical properties of the earlier result.
BibTeX:
@article{Baruah2010,
  author = {Baruah, Sanjoy K. and Bonifaci, Vincenzo and Marchetti--Spaccamela, Alberto and Stiller, Sebastian},
  title = {Improved multiprocessor global schedulability analysis},
  journal = {Real--Time Systems},
  year = {2010},
  volume = {46},
  number = {1},
  pages = {3--24},
  url = {papers/Baruah2010.pdf},
  doi = {http://doi.org/10.1007/s11241--010-9096-3}
}
Baruah, S.K., Bonifaciy, V., Marchetti-Spaccamela, A., Stougie, L. and Wiese, A. A Generalized Parallel Task Model for Recurrent Real--time Processes 2012 Proceedings of the 33rd IEEE Real--Time Systems Symposium (RTSS), pp. 63-72  inproceedings DOI URL 
Abstract: A model is considered for representing recurrent precedence--constrained tasks that are to execute on multiprocessor platforms. A recurrent task is specified as a directed a cyclic graph (DAG), a period, and a relative deadline. Each vertex of the DAG represents a sequential job, while the edges of the DAG represent precedence constraints between these jobs. All the jobs of the DAG are released simultaneously and need to complete execution within the specified relative deadline of their release. The task may release jobs in this manner an unbounded number of times, with successive releases occurring at least the specified period apart. The scheduling problem is to determine whether such a recurrent task can be scheduled to always meet all deadlines upon a specified number of processors that are dedicated for the use of this task. This problem is shown to be computationally intractable, but amenable to efficient approximate solutions. EDF is shown to be a good approximate scheduling algorithm. Polynomial and pseudo-polynomial schedulability tests, of differing effectiveness, are presented for determining whether a given task can be scheduled by EDF to always meet all deadlines on a specified number of processors.
BibTeX:
@inproceedings{Baruah2012b,
  author = {Baruah, Sanjoy K. and Bonifaciy, Vincenzo and Marchetti--Spaccamela, Alberto and Stougie, Leen and Wiese, Andreas},
  title = {A Generalized Parallel Task Model for Recurrent Real--time Processes},
  booktitle = {Proceedings of the 33rd IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {63--72},
  url = {papers/Baruah2012b.pdf},
  doi = {http://doi.org/10.1109/RTSS.2012.59}
}
Baruah, S.K. and Burns, A. Sustainable scheduling analysis 2006 Proceedings of the 27th IEEE Real--Time Systems Symposium (RTSS), pp. 159-168  inproceedings DOI URL 
Abstract: A schedulability test is defined to be sustainable if any task system deemed schedulable by the test remains so if it behaves "better" than mandated by its system specifications. We provide a formal definition of sustainability, and subject the concept to systematic analysis in the context of the uniprocessor scheduling of periodic and sporadic task systems. We argue that it is in general good engineering practice to use sustainable tests if possible, and classify common uniprocessor schedulability tests according to whether they are sustainable or not.
BibTeX:
@inproceedings{Baruah2006,
  author = {Baruah, Sanjoy K. and Burns, Alan},
  title = {Sustainable scheduling analysis},
  booktitle = {Proceedings of the 27th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {159--168},
  url = {papers/Baruah2006.pdf},
  doi = {http://doi.org/10.1109/RTSS.2006.47}
}
Baruah, S.K., Burns, A. and Davis, R.I. Response--Time Analysis for Mixed Criticality Systems 2011 Proceedings of the 32nd IEEE Real--Time Systems Symposium (RTSS), pp. 34-43  inproceedings DOI URL 
Abstract: Many safety--critical embedded systems are subject to certification requirements. However, only a subset of the functionality of the system may be safety-critical and hence subject to certification, the rest of the functionality is non safety-critical and does not need to be certified, or is certified to a lower level. The resulting mixed criticality system offers challenges both for static schedulability analysis and run-time monitoring. This paper considers a novel implementation scheme for fixed priority uniprocessor scheduling of mixed criticality systems. The scheme requires that jobs have their execution times monitored (as is usually the case in high integrity systems). An optimal priority assignment scheme is derived and sufficient response-time analysis is provided. The new scheme formally dominates those previously published. Evaluations illustrate the benefits of the scheme.
BibTeX:
@inproceedings{Baruah2011a,
  author = {Baruah, Sanjoy K. and Burns, Alan and Davis, Robert Ian},
  title = {Response--Time Analysis for Mixed Criticality Systems},
  booktitle = {Proceedings of the 32nd IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2011},
  pages = {34--43},
  url = {papers/Baruah2011a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2011.12}
}
Baruah, S.K. and Carpenter, J. Multiprocessor fixed--priority scheduling with restricted interprocessor migrations 2003 Proceedings of the 15th Euromicro Conference on Real--time Systems (ECRTS), pp. 195-202  inproceedings DOI URL 
Abstract: The priority--driven scheduling of periodic and sporadic task systems upon identical multiprocessor platforms is considered, under the restrictions that (i) each job may be assigned exactly one priority throughout its lifetime, and (ii) each job may execute upon only a single processor. It is shown that the feasibility-analysis under these restrictions is intractable (NP-hard in the strong sense). A scheduling algorithm is presented that satisfies these restrictions, and that has a worst-case utilization bound comparable to the worst-case utilization bounds of partitioned scheduling algorithms, and of scheduling algorithms that retain the priority-assignment restriction but allow arbitrary interprocessor migration.
BibTeX:
@inproceedings{Baruah2003b,
  author = {Baruah, Sanjoy K. and Carpenter, John},
  title = {Multiprocessor fixed--priority scheduling with restricted interprocessor migrations},
  booktitle = {Proceedings of the 15th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2003},
  pages = {195--202},
  url = {papers/Baruah2003b.pdf},
  doi = {http://doi.org/10.1109/EMRTS.2003.1212744}
}
Baruah, S.K., Chattopadhyay, B., Li, H. and Shin, I. Mixed--criticality scheduling on multiprocessors   unpublished URL 
Abstract: The scheduling of mixed--criticality implicit-deadline sporadic task systems on identical multiprocessor platforms is considered. Two approaches, one for global and another for partitioned scheduling, are described. Theoretical analyses and simulation experiments are used to compare the global and partitioned scheduling approaches.
BibTeX:
@unpublished{Baruaha,
  author = {Baruah, Sanjoy K. and Chattopadhyay, Bipasa and Li, Haohan and Shin, Insik},
  title = {Mixed--criticality scheduling on multiprocessors},
  url = {papers/Baruaha.pdf}
}
Baruah, S.K., Chen, D., Gorinsky, S. and Mok, A.K.-L. Generalized Multiframe Tasks 1999 Real--Time Systems
Vol. 17(1), pp. 5-22 
article DOI URL 
Abstract: A new model for sporadic task systems is introduced. This model— the generalized multiframe task model—further generalizes both the conventional sporadic--tasks model, and the more recent multiframe model of Mok and Chen. A framework for determining feasibility for a wide variety of task systems is established; this framework is applied to this task model to obtain a feasibility-testing algorithm that runs in time pseudo-polynomial in the size of the input for all systems of such tasks whose densities are bounded by a constant less than one.
BibTeX:
@article{Baruah1999,
  author = {Baruah, S. K. and Chen, Deji and Gorinsky, Sergey and Mok, Aloysius Ka--Lau},
  title = {Generalized Multiframe Tasks},
  journal = {Real--Time Systems},
  year = {1999},
  volume = {17},
  number = {1},
  pages = {5--22},
  url = {papers/Baruah1999.pdf},
  doi = {http://doi.org/10.1023/A:1008030427220}
}
Baruah, S.K., Cohen, N.K., Plaxton, C.G. and Varvel, D.A. Proportionate Progress: A Notion of Fairness in Resource Allocation 1996 Algorithmica
Vol. 15(6), pp. 600-625 
article DOI URL 
Abstract: Givenasetofntasksandmresources, whereeachtaskxhasarationalweightx.w= x.e/x.p,O < x.w < 1, a periodic schedule is one that allocates a resource tO a task x for exactly x.e time units in each interval [x.p. k, x.p. (k + 1)) for all k   N. We define a notion of proportionate progress, called P--fairness, and use it to design an efficient algorithm which solves the periodic scheduling problem.
BibTeX:
@article{Baruah1996,
  author = {Baruah, Sanjoy K. and Cohen, N. K. and Plaxton, Charles Gregory and Varvel, D. A.},
  title = {Proportionate Progress: A Notion of Fairness in Resource Allocation},
  journal = {Algorithmica},
  year = {1996},
  volume = {15},
  number = {6},
  pages = {600--625},
  url = {papers/Baruah1996.pdf},
  doi = {http://doi.org/10.1007/BF01940883}
}
Baruah, S.K. and Fisher, N.W. Global Fixed--Priority Scheduling of Arbitrary-Deadline Sporadic Task Systems 2008
Vol. 4904/2008Proceedings of the 9th International Conference on Distributed Computing and Networking (ICDCN), pp. 215-226 
inproceedings DOI URL 
Abstract: Fixed Task Priority (FTP) scheduling algorithms are priority--driven scheduling algorithms in which all jobs generated by each recurrent task are restricted to have the same priority. The multiprocessor FTP scheduling of sporadic task systems is studied in this paper. A new sufficient schedulability test is presented and proved correct. It is shown that this test offers non-trivial quantitative guarantees, including a processor speedup bound.
BibTeX:
@inproceedings{Baruah2008a,
  author = {Baruah, Sanjoy K. and Fisher, Nathan Wayne},
  title = {Global Fixed--Priority Scheduling of Arbitrary-Deadline Sporadic Task Systems},
  booktitle = {Proceedings of the 9th International Conference on Distributed Computing and Networking (ICDCN)},
  publisher = {Springer},
  year = {2008},
  volume = {4904/2008},
  pages = {215--226},
  url = {papers/Baruah2008a.pdf},
  doi = {http://doi.org/10.1007/978--3-540-77444-0_20}
}
Baruah, S.K. and Fisher, N.W. A Dynamic Programming Approach to Task Partitioning upon Memory--constrained Multiprocessors 2004 Proceedings of the 10th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 9pp  inproceedings URL 
Abstract: Most prior theorical research on partitioning algorithms for real--time multiprocessor platforms has focused on ensuring that the cumulative computing requirements of the tasks assigned to each processor does not exceed the processor's processing power. However, many multiprocessor platforms have only limited amounts of local per-processor memory; if the memory limitation of a processor is not respected, trashing between "main" memory and processor's local memory may occur during run-time and may result in performance degradation.
BibTeX:
@inproceedings{Baruah2004,
  author = {Baruah, Sanjoy K. and Fisher, Nathan Wayne},
  title = {A Dynamic Programming Approach to Task Partitioning upon Memory--constrained Multiprocessors},
  booktitle = {Proceedings of the 10th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {Springer--Verlag},
  year = {2004},
  pages = {9pp},
  url = {papers/Baruah2004.pdf}
}
Baruah, S.K., Funk, S.H. and Goossens, J. Robustness Results Concerning EDF Scheduling upon Uniform Multiprocessors 2003 IEEE Transactions on Computers
Vol. 52(9), pp. 1185-1195 
article DOI URL 
Abstract: Each processor in a uniform multiprocessor machine is characterized by a speed or computing capacity, with the interpretation that a job executing on a processor with speed s for t time units completes (s x t) units of execution. The earliest--deadline-first (EDF) scheduling of hard-real-time systems upon uniform multiprocessor machines is considered. It is known that online algorithms tend to perform very poorly in scheduling such hard-real-time systems on multiprocessors; resource-augmentation techniques are presented here that permit online algorithms in general (EDF in particular) to perform better than may be expected given these inherent limitations. It is shown that EDF scheduling upon uniform multiprocessors is robust with respect to both job execution requirements and processor computing capacity.
BibTeX:
@article{Baruah2003a,
  author = {Baruah, Sanjoy K. and Funk, Shelby Hyatt and Goossens, Joël},
  title = {Robustness Results Concerning EDF Scheduling upon Uniform Multiprocessors},
  journal = {IEEE Transactions on Computers},
  year = {2003},
  volume = {52},
  number = {9},
  pages = {1185--1195},
  url = {papers/Baruah2003a.pdf},
  doi = {http://doi.org/10.1109/TC.2003.1228513}
}
Baruah, S.K., Gehrke, J.E. and Plaxton, C.G. Fast scheduling of periodic tasks on multiple resources 1995 Proceedings of the 9th International Parallel Processing Symposium (IPPS), pp. 280-288  inproceedings DOI URL 
Abstract: Given n periodic tasks, each characterized by an execution requirement and a period, and m identical copies of a resource, the periodic scheduling problem is concerned with generating a schedule for the n tasks on the m resources. We present an algorithm that schedules every feasible instance of the periodic scheduling problem, and runs in O(minmlgn,n) time per slot scheduled.
BibTeX:
@inproceedings{Baruah1995,
  author = {Baruah, Sanjoy K. and Gehrke, Johannes E. and Plaxton, Charles Gregory},
  title = {Fast scheduling of periodic tasks on multiple resources},
  booktitle = {Proceedings of the 9th International Parallel Processing Symposium (IPPS)},
  publisher = {IEEE Computer Society 1995},
  year = {1995},
  pages = {280--288},
  url = {papers/Baruah1995.pdf},
  doi = {http://doi.org/10.1109/IPPS.1995.395946}
}
Baruah, S.K. and Goossens, J. Deadline Monotonic Scheduling on Uniform Multiprocessors 2008 Proceedings of the 12th International Conference on Principles of Distributed Systems (OPODIS), pp. 89-104  inproceedings DOI URL 
Abstract: The scheduling of sporadic task systems upon uniform multiprocessor platforms using global Deadline Monotonic algorithm is studied. A sufficient schedulability test is presented and proved correct. It is shown that this test offers non--trivial quantitative guarantees, in the form of a processor speedup bound.
BibTeX:
@inproceedings{Baruah2008,
  author = {Baruah, Sanjoy K. and Goossens, Joël},
  title = {Deadline Monotonic Scheduling on Uniform Multiprocessors},
  booktitle = {Proceedings of the 12th International Conference on Principles of Distributed Systems (OPODIS)},
  publisher = {Springer},
  year = {2008},
  pages = {89--104},
  url = {papers/Baruah2008.pdf},
  doi = {http://doi.org/10.1007/978--3-540-92221-6_8}
}
Baruah, S.K. and Goossens, J. Rate--monotonic scheduling on uniform multiprocessors 2003 Proceedings of the 23rd International Conference on Distributed Computing Systems (ICDCS), pp. 360-366  inproceedings DOI URL 
Abstract: Each processor in a uniform multiprocessor machine is characterized by a speed or computing capacity, with the interpretation that a job executing on a processor with speed s for t time units completes (s × t) units of execution. The scheduling of systems of periodic tasks on uniform multiprocessor platforms using the rate--monotonic scheduling algorithm is considered here. A simple, sufficient test is presented for determining whether a given periodic task system will be successfully scheduled by algorithm upon a particular uniform multiprocessor platform-this test generalizes earlier results concerning rate-monotonic scheduling upon identical multiprocessor platforms.
BibTeX:
@inproceedings{Baruah2003,
  author = {Baruah, Sanjoy K. and Goossens, Joël},
  title = {Rate--monotonic scheduling on uniform multiprocessors},
  booktitle = {Proceedings of the 23rd International Conference on Distributed Computing Systems (ICDCS)},
  publisher = {IEEE Computer Society},
  year = {2003},
  pages = {360--366},
  url = {papers/Baruah2003.pdf},
  doi = {http://doi.org/10.1109/ICDCS.2003.1203485}
}
Baruah, S.K. and Goossens, J. The Static--Priority Scheduling of Periodic Task Systems upon Identical Multiprocessor Platforms 2003 Proceedings of the IASTED International Conference on Parallel and Distributed Computing and Systems (ICPDCS), pp. 427-432  inproceedings URL 
Abstract: We study the global, static--priority scheduling of periodic task systems upon multiprocessor platforms comprised of identical processors. We improve upon earlier results in several ways: (i) we present an improved test for determining whether a task system is successfully scheduled by the (multiprocessor extension of the) rate-monotonic scheduling algorithm. (ii) For periodic task systems that cannot be scheduled using rate-monotonic priorities, we propose a new polynomial-time algorithm for assigning priorities in a manner that is not rate-monotonic; this new priorityassignment algorithm successfully finds good priority assignments for some periodic task systems that are not RM-feasible.
BibTeX:
@inproceedings{Baruah2003c,
  author = {Baruah, Sanjoy K. and Goossens, Joël},
  title = {The Static--Priority Scheduling of Periodic Task Systems upon Identical Multiprocessor Platforms},
  booktitle = {Proceedings of the IASTED International Conference on Parallel and Distributed Computing and Systems (ICPDCS)},
  year = {2003},
  pages = {427--432},
  url = {papers/Baruah2003c.pdf}
}
Baruah, S.K. and Guo, Z. Scheduling Mixed--Criticality Implicit-Deadline Sporadic Task Systems upon a Varying-Speed Processor 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 31-40  inproceedings DOI URL 
Abstract: A mixed criticality (MC) workload consists of components of varying degrees of importance (or “criticalites”). The problem of executing a MC workload, modeled as a collection of independent implicit--deadline sporadic tasks executing upon a preemptive uniprocessor, is considered. Suitable scheduling strategies are devised for scheduling such systems despite uncertainty and unpredictability in both the amount of execution needed by the tasks, and the effective speed of the processor. These scheduling strategies allow for simultaneously making efficient use of platform resources and ensuring the correctness of the more critical workload components at greater levels of assurance.
BibTeX:
@inproceedings{Baruah2014,
  author = {Baruah, Sanjoy K. and Guo, Zhishan},
  title = {Scheduling Mixed--Criticality Implicit-Deadline Sporadic Task Systems upon a Varying-Speed Processor},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {31--40},
  url = {papers/Baruah2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.15}
}
Baruah, S.K., Li, H. and Stougie, L. Towards the Design of Certifiable Mixed--criticality Systems 2010 Proceedings of the 16th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS), pp. 13-22  inproceedings DOI URL 
Abstract: Many safety--critical embedded systems are subject to certification requirements; some systems may be required to meet multiple sets of certification requirements, from different certification authorities. Certification requirements in such "mixed-criticality" systems give rise to some interesting scheduling problems, that cannot be satisfactorily addressed using techniques from conventional scheduling theory. In this paper, we propose a formal model for representing such mixed-criticality workloads. We demonstrate the intractability of determining whether a system specified in this model can be scheduled to meet all its certification requirements. For dual-criticality systems - systems subject to two sets of certification requirements - we quantify, via the metric of processor speedup factor, the effectiveness of 2 techniques (reservation-based scheduling and priority-based scheduling) that are widely used in scheduling such mixed-criticality systems.
BibTeX:
@inproceedings{Baruah2010b,
  author = {Baruah, Sanjoy K. and Li, Haohan and Stougie, Leen},
  title = {Towards the Design of Certifiable Mixed--criticality Systems},
  booktitle = {Proceedings of the 16th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {13--22},
  url = {papers/Baruah2010b.pdf},
  doi = {http://doi.org/10.1109/RTAS.2010.10}
}
Baruah, S.K., Mok, A.K.-L. and Rosier, L.E. Preemptively Scheduling Hard--Real-Time Sporadic Tasks on One Processor 1990 Proceedings of the 11th IEEE Real--Time Systems Symposium (RTSS), pp. 182-190  inproceedings DOI URL 
Abstract: Consideration is given to the preemptive scheduling of hard--real-time sporadic task systems on one processor. The authors first give necessary and sufficient conditions for a sporadic task system to be feasible (i.e., schedulable). The conditions cannot, in general, be tested efficiently (unless P=NP). They do, however, lead to a feasibility test that runs in efficient pseudo-polynomial time for a very large percentage of sporadic task systems.
BibTeX:
@inproceedings{Baruah1990a,
  author = {Baruah, Sanjoy K. and Mok, Aloysius Ka--Lau and Rosier, Louis E.},
  title = {Preemptively Scheduling Hard--Real-Time Sporadic Tasks on One Processor},
  booktitle = {Proceedings of the 11th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1990},
  pages = {182--190},
  url = {papers/Baruah1990a.pdf},
  doi = {http://doi.org/10.1109/REAL.1990.128746}
}
Baruah, S.K., Rosier, L.E. and Howell, R.R. Algorithms and Complexity Concerning the Pre--emptive Scheduling of Periodic Real-Time tasks on one processor 1990 Real--Time Systems
Vol. 2(4), pp. 301-324 
article DOI URL 
Abstract: We investigate the preemptive scheduling of periodic, real--time task systems on one processor. First, we show that when all parameters to the system are integers, we may assume without loss of generality that all preemptions occur at integer time values. We then assume, for the remainder of the paper, that all parameters are indeed integers. We then give as our main lemma both necessary and sufficient conditions for a task system to be feasible on one processor. Although these conditions cannot, in general, be tested efficiently (unless P = NP), they do allow us to give efficient algorithms for deciding feasibility on one processor for certain types of periodic task systems. For example, we give a pseudo-polynomial- time algorithm for synchronous systems whose densities are bounded by a fixed constant less than 1. This algorithm represents an exponential improvement over the previous best algorithm. We also give a polynomial-time algorithm for systems having a fixed number of distinct types of tasks. Furthermore, we are able to use our main lemma to show that the feasibility problem for task systems on one processor is co-NP-complete in the strong sense. In order to show this last result, we first show the Simultaneous Congruences Problem to be NP-complete in the strong sense. Both of these last two results answer questions that have been open for ten years. We conclude by showing that for incomplete task systems, i.e., task systems in which the start times are not specified, the feasibility problem is E_2^P-complete.
BibTeX:
@article{Baruah1990,
  author = {Baruah, Sanjoy K. and Rosier, Louis E. and Howell, Rodney R.},
  title = {Algorithms and Complexity Concerning the Pre--emptive Scheduling of Periodic Real-Time tasks on one processor},
  journal = {Real--Time Systems},
  year = {1990},
  volume = {2},
  number = {4},
  pages = {301--324},
  url = {papers/Baruah1990.pdf},
  doi = {http://doi.org/10.1007/BF01995675}
}
Baruah, S.K. and Vestal, S. Schedulability analysis of sporadic tasks with multiple criticality specifications 2008 Proceedings of the 20th Euromicro Conference on Real--Time Systems (ECRTS), pp. 147-155  inproceedings DOI URL 
Abstract: In a paper that was presented at the recently--concluded real-time systems symposium, Vestal proposed a new real-time task model that is able to represent the fact that the worst-case execution time (WCET) of a single task may be determined to different levels of accuracy with different degrees of confidence. In systems with multiple criticality requirements -different tasks need to be assured of meeting their deadlines with different levels of confidence - such multiple specifications of WCET may be exploited to obtain better processor utilization.This paper conducts a thorough study of the feasibility and schedulability questions for such multi-criticality real-time task systems when implemented upon preemptive uniprocessor platforms.
BibTeX:
@inproceedings{Baruah2008b,
  author = {Baruah, Sanjoy K. and Vestal, Steve},
  title = {Schedulability analysis of sporadic tasks with multiple criticality specifications},
  booktitle = {Proceedings of the 20th Euromicro Conference on Real--Time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {147--155},
  url = {papers/Baruah2008b.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2008.26}
}
Bate, I. and Audsley, N.C. Flexible Design of Complex High--Integrity Systems Using Trade Offs 2004 Proceedings of the 8th International Symposium on High--Assurance Systems Engineering (HASE), pp. 22-31  inproceedings DOI URL 
Abstract: Large--scale complex embedded systems pose unique problems. To reduce overall development times, there is a need to develop the system in a concurrent fashion, involving the development and verification of software at the same time as designing, building and verifying the hardware. This requires a two-phase trade-off analysis approach to the hardware software co-design problem. The first phase is platform independent: it allows system requirements to be met and also supports other important objectives, e.g. scalability, upgradeability. The results of the first phase include deriving requirements and design constraints placed on the platform dependent phase (e.g. resource budgets including time). The second, platform dependent phase, chooses the actual software and hardware implementation that satisfies the requirements derived in phase 1. This paper addresses the first part of the problem through trade-off analysis. This establishes the design decisions in a traceable manner whilst capturing the rationale and assumptions made. It then searches the design space for the solution that best meets the system's objectives. The approach has been developed for the needs of critical systems and has already been applied to the logical design of systems.
BibTeX:
@inproceedings{Bate2004,
  author = {Bate, Iain and Audsley, Neil C.},
  title = {Flexible Design of Complex High--Integrity Systems Using Trade Offs},
  booktitle = {Proceedings of the 8th International Symposium on High--Assurance Systems Engineering (HASE)},
  publisher = {IEEE Computer Society},
  year = {2004},
  pages = {22--31},
  url = {papers/Bate2004.pdf},
  doi = {http://doi.org/10.1109/HASE.2004.1281727}
}
Bauer, H. Analyse pire cas de flux hétérogènes dans un réseau embarqué avion 2011 School: Université de Toulouse  phdthesis URL 
BibTeX:
@phdthesis{Bauer2011,
  author = {Bauer, Henri},
  title = {Analyse pire cas de flux hétérogènes dans un réseau embarqué avion},
  school = {Université de Toulouse},
  year = {2011},
  url = {papers/Bauer2011.pdf}
}
Bazargan, K., Kastner, R. and Sarrafzadech, M. Fast Template Placement for Reconfigurable Computing Systems 2000 IEEE Design and Test of Computers
Vol. 17(1), pp. 68-83 
article DOI URL 
Abstract: This article presents fast online placement methods for dynamically reconfigurable systems, as well as offline 3D placement algorithms for statically reconfigurable architectures.
BibTeX:
@article{Bazargan2000,
  author = {Bazargan, Kiarash and Kastner, Ryan and Sarrafzadech, Majid},
  title = {Fast Template Placement for Reconfigurable Computing Systems},
  journal = {IEEE Design and Test of Computers},
  year = {2000},
  volume = {17},
  number = {1},
  pages = {68--83},
  url = {papers/Bazargan2000.pdf},
  doi = {http://doi.org/10.1109/54.825678}
}
Beitollahi, H. and Deconinck, G. Fault--Tolerant Partitioning Scheduling Algorithms in Real-Time Multiprocessor Systems 2006 Proceedings of the 12th Pacific Rim International Symposium on Dependable Computing (PRDC), pp. 296-304  inproceedings DOI URL 
Abstract: This paper presents the performance analysis of several well--known partitioning scheduling algorithms in real-time and fault-tolerant multiprocessor systems. Both static and dynamic scheduling algorithms are analyzed. Partitioning scheduling algorithms, which are studied here, are heuristic algorithms that are formed by combining any of the bin-packing algorithms with any of the schedulability conditions for the Rate-Monotonic (RM) and Earliest-Deadline-First (EDF) policies. A tool is developed which enables to experimentally evaluate the performance of the algorithms from the graph of tasks. The results show that among several partitioning algorithms evaluated, the RM-Small-Task (RMST) algorithm is the best static algorithm and the EDF-Best-Fit (EDF-BF) is the best dynamic algorithm, for non fault-tolerant systems. For faulttolerant systems which require about 49% more processors, the results show that the RM-First-Fit Decreasing Utilization (RM-FFDU) is the best static algorithm and the EDF-BF is the best dynamic algorithm. To decrease the number of processors in faulttolerant systems, the RMST is modified. The results show that the modified RMST decreases the number of required processors between 7% and 78% in comparison with the original RMST, the RM-FFDU and other well-known static partitioning scheduling algorithms.
BibTeX:
@inproceedings{Beitollahi2006,
  author = {Beitollahi, Hakem and Deconinck, Geert},
  title = {Fault--Tolerant Partitioning Scheduling Algorithms in Real-Time Multiprocessor Systems},
  booktitle = {Proceedings of the 12th Pacific Rim International Symposium on Dependable Computing (PRDC)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {296--304},
  url = {papers/Beitollahi2006.pdf},
  doi = {http://doi.org/10.1109/PRDC.2006.34}
}
Benoit, A., Canon, L.-C., Jeannot, E. and Robert, Y. Reliability of task graph schedules with transient and fail--stop failures: complexity and algorithms 2012 Journal of Scheduling
Vol. 15(5), pp. 615-627 
article DOI URL 
Abstract: This paper deals with the reliability of task graph schedules with transient and fail--stop failures. While computing the reliability of a given schedule is easy in the absence of task replication, the problem becomes much more difficult when task replication is used. We fill a complexity gap of the scheduling literature: our main result is that this reliability problem is #P′-Complete (hence at least as hard as NP-Complete problems), both for transient and for fail-stop processor failures. We also study the evaluation of a restricted class of schedules, where a task cannot be scheduled before all replicas of all its predecessors have completed their execution. Although the complexity in this case with fail-stop failures remains open, we provide an algorithm to estimate the reliability while limiting evaluation costs, and we validate this approach through simulations.
BibTeX:
@article{Benoit2012,
  author = {Benoit, Anne and Canon, Louis--Claude and Jeannot, Emmanuel and Robert, Yves},
  title = {Reliability of task graph schedules with transient and fail--stop failures: complexity and algorithms},
  journal = {Journal of Scheduling},
  year = {2012},
  volume = {15},
  number = {5},
  pages = {615--627},
  url = {papers/Benoit2012.pdf},
  doi = {http://doi.org/10.1007/s10951--011-0236-y}
}
Berna, B. and Puaut, I. PDPA: Period Driven Task and Cache Partitioning Algorithm for Multi--Core Systems 2012 Proceedings of the 20th International Conference on Real--Time and Network, pp. 181-190  inproceedings DOI URL 
Abstract: Multi--core architectures are well suited to fulfill the increasing performance requirements of embedded real-time systems. However, such systems also require the capacity to estimate the timing behavior of their critical components. Interference between tasks, as they occur on standard multi-core micro-architectures due to cache sharing are still difficult to predict accurately. An alternative is to remove these indirect interferences between tasks through partitioning of the shared cache and through the use of partitioned task scheduling. In this paper, we present a new algorithm for joint task and cache partitioning in multi-core systems scheduled using non-preemptive EDF. The main novelty of the algorithm is to take into account the tasks' period repartition in the task partitioning problem, which is critical in a non-preemptive context. Other task properties such as task cache requirements are also considered to optimize cache partitioning. Experiments show that our algorithm outperforms the state-of-the-art algorithm for tasks and cache partitioning, named IA3 [18], in terms of schedulability, specially when tasks have varied periods.
BibTeX:
@inproceedings{Berna2012,
  author = {Berna, Brice and Puaut, Isabelle},
  title = {PDPA: Period Driven Task and Cache Partitioning Algorithm for Multi--Core Systems},
  booktitle = {Proceedings of the 20th International Conference on Real--Time and Network},
  publisher = {ACM},
  year = {2012},
  pages = {181--190},
  url = {papers/Berna2012.pdf},
  doi = {http://doi.org/10.1145/2392987.2393010}
}
Berten, V., Collette, S. and Goossens, J. Feasibility Test for Multi--Phase Parallel Real-Time Jobs 2009 Proceedings of the Work--in-Progress Session of the 30th IEEE Real-Time Systems Symposium (WiP RTSS), pp. 33-36  inproceedings URL 
Abstract: We consider the scheduling of real--time and parallel tasks on identical multiprocessor platforms (see [1], [2]). We deal with the case where each job may be executed on different processors simultaneously, i.e., we allow job parallelism. Jobs are composed of phases to be executed sequentially. We provide a necessary feasibility test and we believe that our techniques will yield a sufficient test.
BibTeX:
@inproceedings{Berten2009,
  author = {Berten, Vandy and Collette, Sébastien and Goossens, Joël},
  title = {Feasibility Test for Multi--Phase Parallel Real-Time Jobs},
  booktitle = {Proceedings of the Work--in-Progress Session of the 30th IEEE Real-Time Systems Symposium (WiP RTSS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {33--36},
  url = {papers/RTSS09WiPproceedings.pdf}
}
Bertogna, M. Evaluation of Existing Schedulability Tests for Global EDF 2009 Proceedings of the 38th International Conference on Parallel Processing Workshops (ICPPW), pp. 11-18  inproceedings DOI URL 
Abstract: The increasing attention on global scheduling algorithms for identical multiprocessor platforms produced different, independently developed, schedulability tests. However, the existing relations among such tests have not been sufficiently clarified, so that it is difficult to understand which strategy provides the best performances in a particular scenario. In this paper, we will summarize the main existing results for the schedulability analysis of multiprocessor systems scheduled with global EDF, showing, when possible, existing dominance relations. We will compare these algorithms taking into consideration different aspects, namely, run--time complexity, average performances over a randomly generated workload, sustainability properties and speedup factors.
BibTeX:
@inproceedings{Bertogna2009,
  author = {Bertogna, Marko},
  title = {Evaluation of Existing Schedulability Tests for Global EDF},
  booktitle = {Proceedings of the 38th International Conference on Parallel Processing Workshops (ICPPW)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {11--18},
  note = {First International Workshop on Real--time Systems on Multicore Platforms: Theory and Practice (XRTS)},
  url = {papers/Bertogna2009.pdf},
  doi = {http://doi.org/10.1109/ICPPW.2009.12}
}
Bertogna, M. Real--Time Scheduling Analysis for Multiprocessor Platforms 2008 School: Scuola Superiore Sant'Anna  phdthesis URL 
BibTeX:
@phdthesis{Bertogna2008,
  author = {Bertogna, Marko},
  title = {Real--Time Scheduling Analysis for Multiprocessor Platforms},
  school = {Scuola Superiore Sant'Anna},
  year = {2008},
  url = {papers/Bertogna2008.pdf}
}
Bertogna, M. and Cirinei, M. Response--Time Analysis for Globally Scheduled Symmetric Multiprocessor Platforms 2007 Proceedings of the 28th IEEE Real--Time Systems Symposium (RTSS), pp. 149-160  inproceedings DOI URL 
Abstract: In the last years, a progressive migration from single processor chips to multi--core computing devices has taken place in the general-purpose and embedded system market. The development of multi-processor systems is already a core activity for the most important hardware companies. A lot of different solutions have been proposed to overcome the physical limits of single core devices and to address the increasing computational demand of modern multimedia applications. The real-time community followed this trend with an increasing number of results adapting the classical scheduling analysis to parallel computing systems. This paper will contribute to refine the schedulability analysis for symmetric multi-processor (SMP) real-time systems composed by a set of periodic and sporadic tasks. We will focus on both fixed and dynamic priority global scheduling algorithms, where tasks can migrate from one processor to another during execution. By increasing the complexity of the analysis, we will show that an improvement is possible over existing schedulability tests, significantly increasing the number of schedulable task sets detected. The added computational effort is comparable to the cost of techniques widely used in the uniprocessor case. We believe this is a reasonable cost to pay, given the intrinsically higher complexity of multi-processor devices.
BibTeX:
@inproceedings{Bertogna2007,
  author = {Bertogna, Marko and Cirinei, Michele},
  title = {Response--Time Analysis for Globally Scheduled Symmetric Multiprocessor Platforms},
  booktitle = {Proceedings of the 28th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {149--160},
  url = {papes/Bertogna2007.pdf},
  doi = {http://doi.org/10.1109/RTSS.2007.31}
}
Bertogna, M., Cirinei, M. and Lipari, G. Schedulability Analysis of Global Scheduling Algorithms on Multiprocessor Platforms 2009 IEEE Transactions on Parallel and Distributed Systems
Vol. 20(4), pp. 553-566 
article DOI URL 
Abstract: This paper addresses the schedulability problem of periodic and sporadic real--time task sets with constrained deadlines preemptively scheduled on a multiprocessor platform composed by identical processors. We assume that a global work-conserving scheduler is used and migration from one processor to another is allowed during a task lifetime. First, a general method to derive schedulability conditions for multiprocessor real-time systems will be presented. The analysis will be applied to two typical scheduling algorithms: earliest deadline first (EDF) and fixed priority (FP). Then, the derived schedulability conditions will be tightened, refining the analysis with a simple and effective technique that significantly improves the percentage of accepted task sets. The effectiveness of the proposed test is shown through an extensive set of synthetic experiments.
BibTeX:
@article{Bertogna2009a,
  author = {Bertogna, Marko and Cirinei, Michele and Lipari, Giuseppe},
  title = {Schedulability Analysis of Global Scheduling Algorithms on Multiprocessor Platforms},
  journal = {IEEE Transactions on Parallel and Distributed Systems},
  year = {2009},
  volume = {20},
  number = {4},
  pages = {553--566},
  url = {papers/Bertogna2009a.pdf},
  doi = {http://doi.org/10.1109/TPDS.2008.129}
}
Bertogna, M., Cirinei, M. and Lipari, G. New Schedulability Tests for Real--Time task sets scheduled by Deadline Monotonic on Multiprocessors 2005 Proceedings of the 14th International Conference on Principles of Distributed Systems (OPODIS)  inproceedings DOI URL 
Abstract: In this paper, we address the problem of schedulability analysis of a set of real--time periodic (or sporadic) tasks on multiprocessor hardware platforms, under fixed priority global scheduling. In a multiprocessor system with M processors, a global scheduler consists of a single queue of ready tasks for all processors, and the scheduler selects the first M tasks to execute on the M processors. We allow preemption and migration of tasks between processors. This paper presents two different contributions. First, we derive a sufficient schedulability test for periodic and sporadic task system scheduled with fixed priority when priorities are assigned according to Deadline Monotonic. This test is efficient when dealing with heavy tasks (i.e. tasks with high utilization). Then, we develop an independent analysis for preperiod deadline systems. This leads to a new schedulability test with density and utilization bounds that are tighter than the existing ones.
BibTeX:
@inproceedings{Bertogna2005,
  author = {Bertogna, Marko and Cirinei, Michele and Lipari, Giuseppe},
  title = {New Schedulability Tests for Real--Time task sets scheduled by Deadline Monotonic on Multiprocessors},
  booktitle = {Proceedings of the 14th International Conference on Principles of Distributed Systems (OPODIS)},
  publisher = {Springer Berlin / Heidelberg},
  year = {2005},
  url = {papers/Bertogna2005.pdf},
  doi = {http://doi.org/10.1007/11795490_24}
}
Bertrand, D. Contribution à la robustesse des systèmes temps réel embarqués -- Approches de dimensionnement du mécanisme de protection temporelle d'AUTOSAR OS 2011 School: Université de Nantes  phdthesis URL 
Abstract: Depuis quelques années, le domaine de l'automobile connaît de grands changements afin d'améliorer la sécurité, le confort ou réduire la consommation. Aujourd'hui, de multiples composants automobiles informatisés sont développés et intégrés. Cependant, ces composants doivent garantir une certaine sûreté de fonctionnement et des composants peu critiques défaillants ne doivent pas engendrer de défaillances, par propagation, sur des composants critiques. Une isolation des composants est donc nécessaire. Notre travail porte sur la robustesse temporelle des systèmes temps réel embarqués. Le domaine automobile est relativement standardisé et un des standards émergents, le standard AUTOSAR OS, spécifie l'organisation des systèmes informatiques embarqués afin de faciliter le développement de systèmes multiconcepteurs, de permettre la réutilisation de composants sur étagères et d'accroître la flexibilité de tout le processus de développement. Nous nous intéressons plus particulièrement au mécanisme de protection temporelle proposé par ce standard qui permet d'isoler temporellement chaque fonction de l'application en détectant une erreur avant qu'une défaillance plus importante ne se produise. Nous proposons dans ce mémoire des techniques de configuration de ce mécanisme par rapport à certains modèles d'application et aux garanties demandées par le concepteur. Une étude de cas réalisée sur une plateforme matérielle d'exécution et sur le système d'exploitation temps réel Trampoline complète l'étude.
BibTeX:
@phdthesis{Bertrand2011,
  author = {Bertrand, Dominique},
  title = {Contribution à la robustesse des systèmes temps réel embarqués -- Approches de dimensionnement du mécanisme de protection temporelle d'AUTOSAR OS},
  school = {Université de Nantes},
  year = {2011},
  url = {papers/Bertrand2011.pdf}
}
Bini, E. The Design Domain of Real--Time Systems 2004 School: Scuola Superiore Sant'Anna  phdthesis URL 
Abstract: The design phase of a Real--Time Systems can be viewed as an optimization problem. The variables represent the possible design parameters. The function to be optimized expresses the overall goal of the design. The Real-Time requirements constrain the design parameter to be within a given domain. In this work two domains are fully described. First we assume a fixed priority scheduler and we characterize the space of all the possible schedulable applications, properly modeled, on a uniprocessor. Then, in the framework of hierarchical scheduling, the domain of "processor shares" is described, given a fixed application.
BibTeX:
@phdthesis{Bini2004b,
  author = {Bini, Enrico},
  title = {The Design Domain of Real--Time Systems},
  school = {Scuola Superiore Sant'Anna},
  year = {2004},
  url = {papers/Bini2004a.pdf}
}
Bini, E. and Baruah, S.K. Efficient computation of response time bounds under fixed--priority scheduling 2007 Proceedings of the 15th Real--Time and Network Systems (RTNS), pp. 95-104  inproceedings URL 
Abstract: All algorithms currently known for computing the response time of tasks scheduled under fixed--priority scheduling have run-time pseudo-polynomial in the representation of the task system. We derive a formula that can be computed in polynomial time for determining an upper bound on response times; our upper bound on response time has the added benefit of being continuous in the task system parameters. We evaluate the effectiveness of our approximation by a series of simulations; these simulations reveal some interesting properties of (exact) response time, which give rise to an open question that we pose as a conjecture. Finally, the proposed upper bound of the response time can be used to test effectively the schedulablity of task sets in time linear with the number of tasks.
BibTeX:
@inproceedings{Bini2007,
  author = {Bini, Enrico and Baruah, Sanjoy K.},
  title = {Efficient computation of response time bounds under fixed--priority scheduling},
  booktitle = {Proceedings of the 15th Real--Time and Network Systems (RTNS)},
  year = {2007},
  pages = {95--104},
  url = {papers/Bini2007.pdf}
}
Bini, E. and Buttazzo, G.C. Measuring the Performance of Schedulability Tests 2005 Real--Time Systems
Vol. 30(1-2), pp. 129-154 
article DOI URL 
Abstract: The high computational complexity required for performing an exact schedulability analysis of fixed priority systems has led the research community to investigate new feasibility tests which are less complex than exact tests, but still provide a reasonable performance in terms of acceptance ratio. The performance of a test is typically evaluated by generating a huge number of synthetic task sets and then computing the fraction of those that pass the test with respect to the total number of feasible ones. The resulting ratio, however, depends on the metrics used for evaluating the performance and on the method for generating random task parameters. In particular, an important factor that affects the overall result of the simulation is the probability density function of the random variables used to generate the task set parameters. In this paper we discuss and compare three different metrics that can be used for evaluating the performance of schedulability tests. Then, we investigate how the random generation procedure can bias the simulation results of some specific scheduling algorithm. Finally, we present an efficient method for generating task sets with uniform distribution in a given space, and show how some intuitive solutions typically used for task set generation can bias the simulation results.
BibTeX:
@article{Bini2005,
  author = {Bini, Enrico and Buttazzo, Giorgio C.},
  title = {Measuring the Performance of Schedulability Tests},
  journal = {Real--Time Systems},
  year = {2005},
  volume = {30},
  number = {1--2},
  pages = {129--154},
  url = {papers/Bini2005.pdf},
  doi = {http://doi.org/10.1007/s11241--005-0507-9}
}
Bini, E. and Buttazzo, G.C. Biasing Effects in Schedulability Measures 2004 Proceedings of the 16th Euromicro Conference on Real--time Systems (ECRTS), pp. 196-203  inproceedings DOI URL 
Abstract: The performance of a schedulabilty test is typically evaluated by generating a huge number of synthetic task sets and then computing the fraction of those that pass the test with respect to the total number of feasible ones. The resulting ratio, however, depends on the metrics used for evaluating the performance and on the method for generating random task parameters. In particular, an important factor that affects the overall result of the simulation is the probability sensity function of the random variables used to generate the task set parameters. In this paper we discuss and compare three different metrics that can be used for evaluating the performance of schedulability tests. Then, we investigate how the random generation procedure can bias the simulation results of some specific scheduling algorithm. Finally, we present an efficient method for generating task sets with uniform distribution in a given space, and show how some intuitive solutions typically used for task set generation can bias the simulation results.
BibTeX:
@inproceedings{Bini2004a,
  author = {Bini, Enrico and Buttazzo, Giorgio C.},
  title = {Biasing Effects in Schedulability Measures},
  booktitle = {Proceedings of the 16th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2004},
  pages = {196--203},
  url = {papers/Bini2004a.pdf},
  doi = {http://doi.org/10.1109/EMRTS.2004.1311021}
}
Bini, E. and Buttazzo, G.C. Schedulability Analysis of Periodic Fixed Priority Systems 2004 IEEE Transactions on Computers
Vol. 53(11), pp. 1462-1473 
article DOI URL 
Abstract: Feasibility analysis of fixed priority systems has been widely studied in the real--time literature and several acceptance tests have been proposed to guarantee a set of periodic tasks. They can be divided in two main classes: polynomial time tests and exact tests. Polynomial time tests can efficiently be used for on-line guarantee of real-time applications, where tasks are activated at runtime. These tests introduce a negligible overhead, when executed upon a new task arrival, however provide only a sufficient schedulability condition, which may cause a poor processor utilization. On the other hand, exact tests, which are based on response time analysis, provide a necessary and sufficient schedulability condition, but are too complex to be executed on line for large task sets. As a consequence, for large task sets, they are often executed off line. This paper proposes a novel approach for analyzing the schedulability of periodic task sets on a single processor under an arbitrary fixed priority assignment. Using this approach, we derive a new schedulability test which can be tuned through a parameter to balance complexity versus acceptance ratio, so that it can be used on line to better exploit the processor, based on the available computational power. Extensive simulations show that our test, when used in its exact form, is significantly faster than the current response time analysis methods. Moreover the proposed approach, for its elegance and compactness, offers an explanation of some known phenomena of fixed priority scheduling and could be helpful for further work on schedulability analysis.
BibTeX:
@article{Bini2004,
  author = {Bini, Enrico and Buttazzo, Giorgio C.},
  title = {Schedulability Analysis of Periodic Fixed Priority Systems},
  journal = {IEEE Transactions on Computers},
  year = {2004},
  volume = {53},
  number = {11},
  pages = {1462--1473},
  url = {papers/Bini2004.pdf},
  doi = {http://doi.org/10.1109/TC.2004.103}
}
Bini, E., Buttazzo, G.C. and Buttazzo, G.M. Rate Monotonic Analysis: The Hyperbolic Bound 2003 IEEE Transactions on Computers
Vol. 57(7), pp. 933- 942 
article DOI URL 
Abstract: In this paper, we propose a novel schedulability analysis for verifying the feasibility of large periodic task sets under the rate monotonic algorithm when the exact test cannot be applied on line due to prohibitively long execution times. The proposed test has the same complexity as the original Liu and Layland bound, but it is less pessimistic, thus allowing it to accept task sets that would be rejected using the original approach. The performance of the proposed approach is evaluated with respect to the classical Liu and Layland method and theoretical bounds are derived as a function of n (the number of tasks) and for the limit case of n tending to infinity. The analysis is also extended to include aperiodic servers and blocking times due to concurrency control protocols. Extensive simulations on synthetic tasks sets are presented to compare the effectiveness of the proposed test with respect to the Liu and Layland method and the exact response time analysis.
BibTeX:
@article{Bini2003,
  author = {Bini, Enrico and Buttazzo, Giorgio C. and Buttazzo, Giuseppe M.},
  title = {Rate Monotonic Analysis: The Hyperbolic Bound},
  journal = {IEEE Transactions on Computers},
  year = {2003},
  volume = {57},
  number = {7},
  pages = {933-- 942},
  url = {papers/Bini2003.pdf},
  doi = {http://doi.org/10.1109/TC.2003.1214341}
}
Bini, E., Di Natale, M. and Buttazzo, G.C. Sensitivity Analysis for Fixed--Priority Real-Time Systems 2006 Proceedings of the 18th Euromicro Conference on Real--time Systems (ECRTS), pp. 13-22  inproceedings DOI URL 
Abstract: At early stages in the design of real--time embedded applications, the timing attributes of the computational activities are often incompletely specified or subject to changes. Later in the development cycle, schedulability analysis can be used to check the feasibility of the task set. However, the knowledge of the worst-case response times of tasks is often not sufficient to precisely determine the actions that would correct a non-schedulable design. In these situations, sensitivity analysis provides useful information for changing the implementation, by giving a measure of those computation times that must be reduced to achieve feasibility, or those that can be increased in case of a product extension, or providing the range of feasible periods for selecting the proper task activation rates. In this work, we exploit the concept of feasibility region to propose a faster and more concise solution to the sensitivity analysis problem with respect to existing techniques based on binary search. Furthermore, we show how the formalization of other problems in the feasibility domain, such as managing overloads through elastic scheduling, can be extended to the exact analysis.
BibTeX:
@inproceedings{Bini2006,
  author = {Bini, Enrico and Di Natale, Marco and Buttazzo, Giorgio C.},
  title = {Sensitivity Analysis for Fixed--Priority Real-Time Systems},
  booktitle = {Proceedings of the 18th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {13--22},
  url = {papers/Bini2006.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2006.26}
}
Bini, E., Nguyen, T.H.C., Richard, P. and Baruah, S.K. A Response--Time Bound in Fixed-Priority Scheduling with Arbitrary Deadlines 2009 IEEE Transactions on Computers
Vol. 58(2), pp. 279-286 
article DOI URL 
Abstract: Since worst case response times must be determined repeatedly during the interactive design of real--time application systems, repeated exact computation of such response times would slow down the design process considerably. In this research, we identify three desirable properties of estimates of the exact response times: continuity with respect to system parameters, efficient computability, and approximability. We derive a technique possessing these properties for estimating the worst-case response time of sporadic task systems that are scheduled using fixed priorities upon a preemptive uniprocessor.
BibTeX:
@article{Bini2009,
  author = {Bini, Enrico and Nguyen, Thi Huyen Chaû and Richard, Pascal and Baruah, Sanjoy K.},
  title = {A Response--Time Bound in Fixed-Priority Scheduling with Arbitrary Deadlines},
  journal = {IEEE Transactions on Computers},
  year = {2009},
  volume = {58},
  number = {2},
  pages = {279--286},
  url = {papers/Bini2009.pdf},
  doi = {http://doi.org/10.1109/TC.2008.167}
}
Blasum, H. and Tverdyshev, S. From a DO-178B Certified Separation Kernel to Common Criteria Security Certification 2011 SAE Technical Paper  inproceedings DOI URL 
Abstract: DO-178B avionic software safety has been largely based upon the assumption that rigorous development and verification processes are uniformly applied to the entire product (that is typically small or developed from scratch and is extensively tested). On the other hand, security certification by the Common Criteria (CC) traditionally has had also in mind the analysis and gradual improvement of existing systems. For such scenarios, just redoing the entire design is not feasible. This leads to a slightly different emphasis in the presentation of artifacts which is of interest not only in a CC certification context but also when for example reviewing requirement-based descriptions of systems.In cooperation with the DFKI evaluation laboratory, we have drafted a security target instantiating security properties (Security Functional Requirements, SFRs) of the PikeOS separation kernel that has undergone certification for DO-178B. The security target initially had been based on the Separation Kernel Protection Profile (SKPP) but is now done stand-alone, without using a protection profile, compatible with the current version of the CC. In the German research project SeSaM [SeS11] we prepare Common Criteria certification artifacts for a DO-178B certified separation kernel for a high-level CC certification. We report on our approach and experiences generating artifacts from a DO-178B/DO-178C perspective and on lessons learned when dealing with the CC.
BibTeX:
@inproceedings{Blasum2011,
  author = {Blasum, Holger and Tverdyshev, Sergey},
  title = {From a DO-178B Certified Separation Kernel to Common Criteria Security Certification},
  booktitle = {SAE Technical Paper},
  publisher = {SAE International},
  year = {2011},
  url = {http://dx.doi.org/10.4271/2011-01-2777},
  doi = {http://doi.org/10.4271/2011-01-2777}
}
Block, A.D., Leontyev, H., Brandenburg, B.B. and Anderson, J.H. A Flexible Real--Time Locking Protocol for Multiprocessors 2007 Proceedings of the 13th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 47-56  inproceedings DOI URL 
Abstract: Real--time scheduling algorithms for multiprocessor systems have been the subject of considerable recent interest. For such an algorithm to be truly useful in practice, support for semaphore-based locking must be provided. However, for many global scheduling algorithms, no such mechanisms have been proposed. Furthermore, in the partitioned case, most prior semaphore schemes are either inefficient or restrict critical sections considerably. In this paper, a new flexible multiprocessor locking scheme is presented that can be applied under both partitioning and global scheduling. This scheme allows unrestricted critical-section nesting, but has been designed to deal with the common case of short non-nested accesses efficiently.
BibTeX:
@inproceedings{Block2007,
  author = {Block, Aaron David and Leontyev, Hennadiy and Brandenburg, Björn B. and Anderson, James H.},
  title = {A Flexible Real--Time Locking Protocol for Multiprocessors},
  booktitle = {Proceedings of the 13th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {47--56},
  url = {papers/Block2007.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2007.8}
}
Bonifaci, V., Marchetti-Spaccamela, A. and Stiller, S. A Constant--Approximate Feasibility Test for Multiprocessor Real-Time Scheduling 2008
Vol. 5193/2008Proceedings of the 16th Annual European Symposium on Algorithms (ESA), pp. 210-221 
inproceedings DOI URL 
Abstract: Abstract. We devise the first constant--approximate feasibility test for sporadic multiprocessor real-time scheduling. We give an algorithm that, given a task system and ε > 0, correctly decides either that the task system can be scheduled using the earliest deadline first algorithm on m speed-(2 − 1/m + ε) machines, or that the system is infeasible for m speed-1 machines. The running time of the algorithm is polynomial in the size of the task system and 1/ε. We also provide an improved bound trading off speed for additional machines. Our analysis relies on a new concept for counting the workload of an interval, that might also turn useful for analyzing other types of task systems.
BibTeX:
@inproceedings{Bonifaci2008,
  author = {Bonifaci, Vincenzo and Marchetti--Spaccamela, Alberto and Stiller, Sebastian},
  title = {A Constant--Approximate Feasibility Test for Multiprocessor Real-Time Scheduling},
  booktitle = {Proceedings of the 16th Annual European Symposium on Algorithms (ESA)},
  publisher = {Springer},
  year = {2008},
  volume = {5193/2008},
  pages = {210--221},
  url = {papers/Bonifaci2008.pdf},
  doi = {http://doi.org/10.1007/978--3-540-87744-8_18}
}
Bordoloi, U.D. and Samii, S. The Frame Packing Problem for CAN--FD 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 284-293  inproceedings DOI URL 
Abstract: CAN with flexible data rate (CAN--FD) allows transmission of larger payloads compared to standard CAN. However, efficient utilization of CAN-FD bandwidth space calls for a systematic strategy. The challenge arises from the nature of the frame sizes stipulated by CAN-FD as well as the heterogeneity of the periods of the messages and the signals. In this paper, we formulate a frame packing problem for CAN-FD with the optimization objective of bandwidth utilization while meeting temporal constraints. As part of the solution, first, we propose a formula to compute the best-case and the worst-case transmission times of the CAN-FD frames. Thereafter, we propose a framework that solves the optimization problem in pseudo-polynomial time. Experiments show the gains achieved by our framework. The results also show that, when applied to standard CAN, our heuristic provides improved results over existing techniques.
BibTeX:
@inproceedings{Bordoloi2014,
  author = {Bordoloi, Unmesh D. and Samii, Soheil},
  title = {The Frame Packing Problem for CAN--FD},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {284--293},
  url = {papers/Bordoloi2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.8}
}
Bougueroua, L. Conception de systèmes temps réel déterministes en environnement incertain 2007 School: Université Paris XII  phdthesis  
BibTeX:
@phdthesis{Bougueroua2007,
  author = {Lamine Bougueroua},
  title = {Conception de systèmes temps réel déterministes en environnement incertain},
  school = {Université Paris XII},
  year = {2007}
}
Bougueroua, L., George, L. and Midonnet, S. Dealing with execution--overruns to improve the temporal robustness of real-time systems scheduled FP and EDF 2007 Proceedings of the 2nd International Conference on Systems (ICONS), pp. 8  inproceedings DOI URL 
Abstract: This paper presents a mechanism for execution--overrun management in preemptive real-time systems composed of sporadic tasks. We consider faults due to Worst Case Execution Time violations. Based on fault prevention, we determine the allowance of a task defined as the maximum extra duration that can be granted to a faulty task without compromising the timeliness constraints of the tasks. We propose a solution to implement the allowance principle that we call the Latest Execution Time (LET), defined for a task as the latest absolute time a faulty task can proceed with its execution without compromising the real-time constraints of all the tasks in the system. This mechanism enables to cope with execution overruns before a deadline miss and is not based on execution overruns handlers. We show how to determine the LET based on existing real-time feasibility conditions for Fixed Priority (FP) and Earliest Deadline First (EDF) schedulings. We compare the performances of the LET mechanism with FP and EDF scheduling to classical execution overrun management solutions.
BibTeX:
@inproceedings{Bougueroua2007a,
  author = {Bougueroua, Lamine and George, Laurent and Midonnet, Serge},
  title = {Dealing with execution--overruns to improve the temporal robustness of real-time systems scheduled FP and EDF},
  booktitle = {Proceedings of the 2nd International Conference on Systems (ICONS)},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {8},
  url = {papers/Bougueroua2007a.pdf},
  doi = {http://doi.org/10.1109/ICONS.2007.18}
}
Bougueroua, L., George, L. and Midonnet, S. An execution overrun management mechanism for the temporal robustness of Java real--time systems 2006 Proceedings of the 4th workshop on Java Technologies for Real--time Embedded Systems (JTRES), pp. 188-195  inproceedings DOI URL 
Abstract: This paper presents a mechanism for execution--overrun management in real-time systems. Based on fault prevention, we determine the Latest Execution Time (LET) of a task defined as the latest absolute time a faulty task can proceed with its execution without compromising the real-time constraints of all the tasks in the system. This mechanism enables to cope with execution overruns before a deadline miss. LET use the allowance notion which depends on free CPU resources. We show how to determine the LET based on existing real-time feasibility conditions for fixed scheduling FP/HPF. We then integrate the LET in an existing RTSJ compliant system and analyze its performances.
BibTeX:
@inproceedings{Bougueroua2006,
  author = {Lamine Bougueroua and Laurent George and Serge Midonnet},
  title = {An execution overrun management mechanism for the temporal robustness of Java real--time systems},
  booktitle = {Proceedings of the 4th workshop on Java Technologies for Real--time Embedded Systems (JTRES)},
  publisher = {ACM},
  year = {2006},
  pages = {188--195},
  url = {papers/Bougueroua2006.pdf},
  doi = {http://doi.org/10.1145/1167999.1168030}
}
Brandenburg, B.B. A Synchronous IPC Protocol for Predictable Access to Shared Resources in Mixed--Criticality Systems 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 196-206  inproceedings DOI URL 
Abstract: In mixed--criticality systems, highly critical tasks must be temporally and logically isolated from faults in lower-criticality tasks. Such strict isolation, however, is difficult to ensure even for independent tasks, and has not yet been attained if low- and high-criticality tasks share resources subject to mutual exclusion constraints (e.g., shared data structures, peripheral I/O devices, or OS services), as it is often the case in practical systems.
Taking a pragmatic, systems--oriented point of view, this paper argues that traditional real-time locking approaches are unsuitable in a mixed-criticality context: locking is a cooperative activity and requires trust, which is inherently in conflict with the paramount isolation requirements. Instead, a solution based on resource servers (in the microkernel sense) is proposed, and MC-IPC, a novel synchronous multiprocessor IPC protocol for invoking such servers, is presented.
The MC--IPC protocol enables strict temporal and logical isolation among mutually untrusted tasks and thus can be used to share resources among tasks of different criticalities. It is shown to be practically viable with a prototype implementation in LITMUS RT and validated with a case study involving several antagonistic failure modes. Finally, MC-IPC is shown to offer analytical benefits in the context of Vestal’s mixed-criticality task model.
BibTeX:
@inproceedings{Brandenburg2014,
  author = {Brandenburg, Björn B.},
  title = {A Synchronous IPC Protocol for Predictable Access to Shared Resources in Mixed--Criticality Systems},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {196--206},
  url = {papers/Brandenburg2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.37}
}
Brandenburg, B.B. Scheduling and Locking in Multiprocessor Real--Time Operating Systems 2011 School: University of North Carolina  phdthesis URL 
Abstract: With the widespread adoption of multicore architectures, multiprocessors are now a standard deployment platform for (soft) real--time applications. This dissertation addresses two questions fundamental to the design of multicore-ready real-time operating systems: (1) Which scheduling policies offer the greatest flexibility in satisfying temporal constraints; and (2) which locking algorithms should be used to avoid unpredictable delays? With regard to Question 1, LITMUSRT , a real-time extension of the Linux kernel, is presented and its design is discussed in detail. Notably, LITMUSRT implements link-based scheduling, a novel approach to controlling blocking due to non-preemptive sections. Each implemented scheduler (22 configurations in total) is evaluated under consideration of overheads on a 24-core Intel Xeon platform. The experiments show that partitioned earliest-deadline first (EDF) scheduling is generally preferable in a hard real-time setting, whereas global and clustered EDF scheduling are effective in a soft real-time setting. With regard to Question 2, real-time locking protocols are required to ensure that the maximum delay due to priority inversion can be bounded a priori. Several spinlock- and semaphore-based multiprocessor real-time locking protocols for mutual exclusion (mutex), reader-writer (RW) exclusion, and k-exclusion are proposed and analyzed. A new category of RW locks suited to worst-case analysis, termed phase-fair locks, is proposed and three efficient phase-fair spinlock implementations are provided (one with few atomic operations, one with low space requirements, and one with constant RMR complexity). Maximum priority-inversion blocking is proposed as a natural complexity measure for semaphore protocols. It is shown that there are two classes of schedulability analysis, namely suspension-oblivious and suspension-aware analysis, that yield two different lower bounds on blocking. Five asymptotically optimal locking protocols are designed and analyzed: a family of mutex, RW, and k-exclusion protocols for global, partitioned, and clustered scheduling that are asymptotically optimal in the suspension-oblivious case, and a mutex protocol for partitioned scheduling that is asymptotically optimal in the suspension-aware case. A LITMUSRT -based empirical evaluation is presented that shows these protocols to be practical.
BibTeX:
@phdthesis{Brandenburg2011,
  author = {Brandenburg, Björn B.},
  title = {Scheduling and Locking in Multiprocessor Real--Time Operating Systems},
  school = {University of North Carolina},
  year = {2011},
  url = {papers/Brandenburg2011.pdf}
}
Brandenburg, B.B. and Anderson, J.H. The OMLP family of optimal multiprocessor real--time locking protocols 2012 Design Automation for Embedded Systems  article DOI URL 
Abstract: This paper presents the first suspension--based multiprocessor real-time locking protocols with asymptotically optimal blocking bounds (under certain analysis assumptions). These protocols can be applied under any global, clustered, or partitioned job-level fixed-priority scheduler and support mutual exclusion, reader-writer exclusion, and k-exclusion constraints. Notably, the reader-writer and k-exclusion protocols are the first analytically-sound suspension-based multiprocessor real-time locking protocols of their kind. To formalize a notion of “optimal blocking,” precise definitions of what constitutes “blocking” in a multiprocessor real-time system are given and a simple complexity metric for real-time locking protocols, called maximum priority-inversion blocking (pi-blocking), is introduced. It is shown that, in a system with m processors, Ω(m) maximum pi-blocking is unavoidable. This bound is shown to be asymptotically tight with the introduction of the O(m) multiprocessor locking protocol (OMLP) family presented herein, which includes protocols that ensure an upper bound on maximum pi-blocking that is approximately within a factor of two of the lower bound. In addition to the coarse-grained asymptotic bounds, detailed blocking bounds suitable for schedulability analysis are derived using holistic blocking analysis. Based on the detailed bounds, the proposed locking protocols are compared with each other and with previously-proposed protocols in an empirical schedulability study involving more than one billion task sets. In this study, the OMLP was found to perform better than two variants of the classic (but non-optimal) multiprocessor priority-ceiling protocol (MPCP).
BibTeX:
@article{Brandenburg2012,
  author = {Brandenburg, Björn B. and Anderson, James H.},
  title = {The OMLP family of optimal multiprocessor real--time locking protocols},
  journal = {Design Automation for Embedded Systems},
  year = {2012},
  note = {online},
  url = {papers/Brandenburg2012.pdf},
  doi = {http://doi.org/10.1007/s10617--012-9090-1}
}
Brandenburg, B.B. and Anderson, J.H. Optimality Results for Multiprocessor Real--Time Locking 2010 Proceedings of the 21st IEEE Real--Time Systems Symposium (RTSS), pp. 49-60  inproceedings DOI URL 
Abstract: When locking protocols are used in real--time systems, bounds on blocking times are required when ensuring timing constraints. While the term “blocking” is well-understood in the context of uniprocessor real-time systems, the same is not true in the multiprocessor case. In this paper, two definitions of blocking are presented that are applicable to suspension-based multiprocessor locking protocols. The need for two definitions arises because of differences in how suspensions are handled in existing schedulability analysis. For each definition, locking protocols are presented that have asymptotically optimal blocking behavior. In particular, protocols are presented for any job-level static-priority global or partitioned scheduling algorithm.
BibTeX:
@inproceedings{Brandenburg2010,
  author = {Brandenburg, Björn B. and Anderson, James H.},
  title = {Optimality Results for Multiprocessor Real--Time Locking},
  booktitle = {Proceedings of the 21st IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {49--60},
  url = {papers/Brandenburg2010.pdf},
  doi = {http://doi.org/10.1109/RTSS.2010.17}
}
Brandenburg, B.B. and Anderson, J.H. On the Implementation of Global Real--Time Schedulers 2009 Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS), pp. 214-224  inproceedings DOI URL 
Abstract: An empirical study of implementation tradeoffs (choice of ready queue implementation, quantum--driven vs. event-driven scheduling, and interrupt handling strategy) affecting global real-time schedulers, and in particular global EDF, is presented. This study, conducted using UNC’s Linux-based LITMUSRT on Sun’s Niagara platform, suggests that implementation tradeoffs can impact schedulability as profoundly as scheduling-theoretic tradeoffs. For most of the considered workloads, implementation scalability proved to not be a key limitation of global EDF on the considered platform. Further, a combination of a parallel heap, event-driven scheduling, and dedicated interrupt handling performed best for most workloads.
BibTeX:
@inproceedings{Brandenburg2009,
  author = {Brandenburg, Björn B. and Anderson, James H.},
  title = {On the Implementation of Global Real--Time Schedulers},
  booktitle = {Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {214--224},
  url = {papers/Brandenburg2009.pdf},
  doi = {http://doi.org/10.1109/RTSS.2009.23}
}
Brandenburg, B.B. and Anderson, J.H. An Implementation of the PCP, SRP, D--PCP, M-PCP, and FMLP Real-Time Synchronization Protocols in LITMUS^RT 2008 Proceedings of the 14th IEEE International Conference on Real--Time and Embedded Computing Systems and Applications (RTCSA), pp. 185-194  inproceedings DOI URL 
Abstract: We extend the FMLP to partitioned static--priority scheduling and derive corresponding worst-case blocking bounds. Further, we present the first implementation of the PCP, SRP, D-PCP, M-PCP, and FMLP synchronization protocols in a unified framework in a general-purpose OS and discuss design issues that were beyond the scope of prior algorithmic-oriented work on real-time synchronization.
BibTeX:
@inproceedings{Brandenburg2008,
  author = {Brandenburg, Björn B. and Anderson, James H.},
  title = {An Implementation of the PCP, SRP, D--PCP, M-PCP, and FMLP Real-Time Synchronization Protocols in LITMUS^RT},
  booktitle = {Proceedings of the 14th IEEE International Conference on Real--Time and Embedded Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {185--194},
  url = {papers/Brandenburg2008.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2008.13}
}
Brandenburg, B.B. and Bastoni, A. The Case for Migratory Priority Inheritance in Linux: Bounded Priority Inversions on Multiprocessors 2012 Proceedings of the 14th Real--Time Linux Workshop (RTLWS), pp. 67-86  inproceedings URL 
Abstract: Linux’s real--time performance crucially depends on priority inheritance because—on uniprocessors—it limits the maximum duration of priority inversion to one critical section per lock while ensuring that tasks remain fully preemptable even when holding locks. Unfortunately, priority inheritance is ineffective on multiprocessors under non-global scheduling (i.e., if some tasks may not execute on every processor) in the sense that it does not prevent unbounded priority inversion in all cases. In fact, as shown in the paper, in a multiprocessor system with priority inheritance, it is possible for a task to suffer from priority inversion as long as in a uniprocessor system without priority inheritance. There is thus currently no predictable locking mechanism suitable for non-global scheduling available in Linux, short of resorting to non-preemptive sections or other latency-increasing mechanisms such as priority boosting. As multicore platforms are becoming more widespread in the embedded domain, this “predictability gap” on multiprocessors limits Linux’s viability as a real-time platform. In this position paper, it is argued that a simple tweak to the priority inheritance algorithm will restore its efficacy on multiprocessors, without breaking POSIX compliance, increasing scheduling latency, or requiring large changes to Linux’s scheduling and locking code. In a nutshell, under the proposed migratory priority inheritance mechanism, inheritance is applied not only to scheduling priorities, but also to processor affinity masks. The need for migratory priority inheritance and its benefits are explained in detail with a sequence of simple examples. Additionally, a prototype implementation within the Linux kernel is described and potential challenges and simplifications are discussed.
BibTeX:
@inproceedings{Brandenburg2012a,
  author = {Brandenburg, Björn B. and Bastoni, Andrea},
  title = {The Case for Migratory Priority Inheritance in Linux: Bounded Priority Inversions on Multiprocessors},
  booktitle = {Proceedings of the 14th Real--Time Linux Workshop (RTLWS)},
  publisher = {Real--Time Linux Foundation},
  year = {2012},
  pages = {67--86},
  url = {papers/Brandenburg2012a.pdf}
}
Brandenburg, B.B., Calandrino, J.M., Block, A.D., Leontyev, H. and Anderson, J.H. Real--Time Synchronization on Multiprocessors: To Block or Not to Block, to Suspend or Spin? 2008 Proceedings of the 14th Real--Time and Embedded Technology and Applications Symposium (RTAS), pp. 342-353  inproceedings DOI URL 
Abstract: In the domain of multiprocessor real--time systems, there has been a wealth of recent work on scheduling, but relatively little work on the equally-important topic of synchronization. When synchronizing accesses to shared resources, four basic options exist: lock-free execution, wait-free execution, spin- based locking, and suspension-based locking. To our knowledge, no empirical multiprocessor-based evaluation of these basic techniques that focuses on real-time systems has ever been conducted before. In this paper, we present such an evaluation and report on our efforts to incorporate synchronization support in the testbed used in this effort.
BibTeX:
@inproceedings{Brandenburg2008a,
  author = {Brandenburg, Björn B. and Calandrino, John M. and Block, Aaron David and Leontyev, Hennadiy and Anderson, James H.},
  title = {Real--Time Synchronization on Multiprocessors: To Block or Not to Block, to Suspend or Spin?},
  booktitle = {Proceedings of the 14th Real--Time and Embedded Technology and Applications Symposium (RTAS)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {342--353},
  url = {papers/Brandenburg2008a.pdf},
  doi = {http://doi.org/10.1109/RTAS.2008.27}
}
Brandenburg, B.B.B. A Fully Preemptive Multiprocessor Semaphore Protocol for Latency--Sensitive Real-Time Applications 2013 Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS), pp. 292-302  inproceedings URL 
Abstract: Independence preservation, a property in real--time locking protocols that isolates latency-sensitive tasks from delays due to unrelated critical sections, is identified, formalized, and studied in detail. The key to independence preservation is to ensure that tasks remain fully preemptive at all times. For example, on uniprocessors, the classic priority inheritance protocol is independence-preserving. It is shown that, on multiprocessors, independence preservation is impossible if job migrations are disallowed. The O(m) independence-preserving protocol (OMIP), a new, asymptotically optimal binary sempahore protocol based on migratory priority inheritance, is proposed and analyzed. The OMIP is the first independence-preserving, real-time, suspension-based locking protocol for clustered job-level fixed-priority scheduling. It is shown to benefit latency-sensitive workloads, both analytically by means of schedulability experiments, and empirically using response-time measurements in LITMUS^RT.
BibTeX:
@inproceedings{Brandenburg2013,
  author = {Brandenburg, Björn B. B.},
  title = {A Fully Preemptive Multiprocessor Semaphore Protocol for Latency--Sensitive Real-Time Applications},
  booktitle = {Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2013},
  pages = {292--302},
  url = {papers/Brandenburg2013.pdf}
}
Brebner, G. A virtual hardware operating system for the Xilinx XC6200 1996
Vol. 1142Proceedings of the 6th International Conference on Field--Programmable Logic and Applications (FPL), pp. 327-336 
inproceedings DOI URL 
Abstract: Computer operating systems relieve a user of the responsibility for managing physical resources, such as processors, memory and input/output devices. The evolution of FPGA technology means that a new resource is available — it is accessed like memory, but can behave like a flexible processor or input/output device. There is a rôle for an operating system in making this resource easy to use, by managing it on behalf of a user. This paper explores the issues involved in such management, in particular the problems involved in presenting a software--oriented user with a larger virtual hardware resource that is implemented using smaller physical FPGA hardware. A prototype operating system, that demonstrates operational solutions to the problems using the Xilinx XC6200 FPGA, is described.
BibTeX:
@inproceedings{Brebner1996,
  author = {Brebner, Gordon},
  title = {A virtual hardware operating system for the Xilinx XC6200},
  booktitle = {Proceedings of the 6th International Conference on Field--Programmable Logic and Applications (FPL)},
  year = {1996},
  volume = {1142},
  pages = {327--336},
  url = {papers/Brebner1996.pdf},
  doi = {http://doi.org/10.1007/3--540-61730-2_35}
}
Brebner, G. and Diessel, O. Chip--Based Reconfigurable Task Management 2001
Vol. 2147Proceedings of the 11th International Conference on Field--Programmable Logic and Applications (FPL), pp. 182-191 
inproceedings DOI URL 
Abstract: Modularity is a key aspect of system design, particularly in the era of system--on-chip. Field-programmable logic (FPL), particularly with the rapid increase in programmable gate counts, is a natural medium to host run-time modularity, that is, a dynamically-varying ensemble of circuit modules. Prior research has presumed the use of an external processor to manage such an ensemble. In this paper, we consider on-chip management, implemented in the FPL itself, based upon a one-dimensional allocation model. We demonstrate an algorithm for on-chip identification of free FPL resource for modules, and an approach to on-chip rearrangement of modules. The latter includes a proposal for a realistic augmentation to existing FPGA reconfiguration architectures. The work represents a key demonstration of how FPL can be used as a first-order computational resource, rather than just as a slave to the microprocessor.
BibTeX:
@inproceedings{Brebner2001,
  author = {Brebner, Gordon and Diessel, Oliver},
  title = {Chip--Based Reconfigurable Task Management},
  booktitle = {Proceedings of the 11th International Conference on Field--Programmable Logic and Applications (FPL)},
  publisher = {Springer Berlin / Heidelberg},
  year = {2001},
  volume = {2147},
  pages = {182--191},
  url = {papers/Brebner2001.pdf},
  doi = {http://doi.org/10.1007/3--540-44687-7_19}
}
Bril, R.J., Altmeyer, S., van den Heuvel, M.M.H.P., Davis, R.I. and Behnam, M. Integrating Cache--Related Pre-Emption Delays into Analysis of Fixed Priority Scheduling with Pre-Emption Thresholds 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 161-172  inproceedings DOI URL 
Abstract: Cache--related pre-emption delays (CRPD) have been integrated into the schedulability analysis of sporadic tasks with constrained deadlines for fixed-priority pre-emptive scheduling (FPPS). This paper generalizes that work by integrating CRPD into the schedulability analysis of tasks with arbitrary deadlines for fixed-priority pre-emption threshold scheduling (FPTS). The analysis is complemented by an optimal threshold assignment algorithm that minimizes CRPD. The paper includes a comparative evaluation of the schedulability ratios of FPPS and FPTS, for constrained-deadline tasks, taking CRPD into account.
BibTeX:
@inproceedings{Bril2014,
  author = {Bril, Reinder J. and Altmeyer, Sebastian and van den Heuvel, Martijn M. H. P. and Davis, Robert Ian and Behnam, Moris},
  title = {Integrating Cache--Related Pre-Emption Delays into Analysis of Fixed Priority Scheduling with Pre-Emption Thresholds},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {161--172},
  url = {papers/Bril2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.25}
}
Bruns, F., Traboulsi, S., Szczesny, D., Gonzalez, E., Xu, Y. and Bilgic, A. An Evaluation of Microkernel-Based Virtualization for Embedded Real-Time Systems 2010 Proceedings of the 22nd Euromicro Conference on Real-Time Systems (ECRTS), pp. 57-65  inproceedings DOI URL 
Abstract: Devices for the mobile market have to satisfy a set of challenging constraints. In addition to the classical power, reliability and cost constraints, modern devices often have to be open to third party applications and at the same time provide a closed and secure environment for system functionality. In current systems, this antagonism is solved by maintaining a physical separation of subsystems with contrary constraints. Virtualization technology is a promising solution to safely merge conflicting subsystems on a single processor which leads to huge cost benefits and higher flexibility. Microkernel based hyper visors are an attractive choice for virtualization, due to their reliability and robustness. However, the involvement of real-time constraints remains a challenging factor. In this paper, we investigate how the security and isolation features of the L4/Fiasco microkernel impact real-time applications by comparing thread switching times and interrupt latencies to those of a conventional Real-time Operating System (RTOS). In addition, we demonstrate that microkernel based systems require significantly more cache resources than traditional systems. Finally, we investigate the performance loss caused by cache and TLB interference imposed by an application subsystem which runs in parallel to the real-time subsystem.
BibTeX:
@inproceedings{Bruns2010,
  author = {Bruns, Felix and Traboulsi, Shadi and Szczesny, David and Gonzalez, Elizabeth and Xu, Yang and Bilgic, Attila},
  title = {An Evaluation of Microkernel-Based Virtualization for Embedded Real-Time Systems},
  booktitle = {Proceedings of the 22nd Euromicro Conference on Real-Time Systems (ECRTS)},
  year = {2010},
  pages = {57--65},
  url = {/papers/Bruns2010.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2010.28}
}
Burchard, A., Liebeherr, J., Oh, Y. and Son, S.H. New strategies for assigning real--time tasks to multiprocessor systems 1995 IEEE Transactions on Computers
Vol. 44(12), pp. 1429-1442 
article DOI URL 
Abstract: Optimal scheduling of real--time tasks on multiprocessor systems is known to be computationally intractable for large task sets. Any practical scheduling algorithm for assigning realtime tasks to a multiprocessor system presents a trade-off between its computational complexity and its performance. In this study, new schedulability conditions are presented for homogeneous multiprocessor systems where individual processors execute the rate-monotonic scheduling algorithm. The conditions are used to develop new strategies for assigning real-time tasks to processors. The performance of the new strategies is shown to be significantly better than suggested by the existing literature. Under the realistic assumption that the load of each real-time task is small compared to the processing speed of each processor, it is shown that the processors can be almost fully utilized.
BibTeX:
@article{Burchard1995,
  author = {Burchard, Almut and Liebeherr, Jörg and Oh, Yingfeng and Son, Sang H.},
  title = {New strategies for assigning real--time tasks to multiprocessor systems},
  journal = {IEEE Transactions on Computers},
  year = {1995},
  volume = {44},
  number = {12},
  pages = {1429--1442},
  url = {papers/Burchard1995.pdf},
  doi = {http://doi.org/10.1109/12.477248}
}
Burguière, C. Modéliser la prédiction de branchement pour le calcul de temps d'exécution pire--cas 2008 School: Université de Toulouse III -- Paul Sabatier  phdthesis URL 
Abstract: The wider and wider use of high--performance processors as part of real-time systems makes it more and more diffcult to guarantee that programs will respect their deadlines. While the computation of Worst-Case Execution Times relies on static analysis of the code, the challenge is to model with enough safety and accuracy the behavior of intrinsically dynamic components. In this report, we focus on the impact of dynamic branch prediction on the worst-case execution time. We present two approaches to model this impact. Local approach examines each branch individually to determine its worst-case number of mispredictions. In the global approach, an ILP system of constraints describes the computation of the branch prediction. Each part of the dynamic branch predictor can be modeled separately: BHT indexing, conflicts on BHT entries and 2-bit counter computation of the prediction. We introduce two branch predictor models: the bimodal predictor and a 2-bit global predictor. We propose a way to compare the eort needed to build the system of constraints that we name modeling complexity. This complexity is quantified as a function of: the number of constraints, the number of variables and the system arity. We analyse the modeling complexity of some branch predictors and we deduce the context of use that fit for the global approach. We examine the differences between the two approaches.
BibTeX:
@phdthesis{Burguiere2008,
  author = {Burguière, Claire},
  title = {Modéliser la prédiction de branchement pour le calcul de temps d'exécution pire--cas},
  school = {Université de Toulouse III -- Paul Sabatier},
  year = {2008},
  url = {papers/Burguiere2008.pdf}
}
Burns, A. and Baruah, S.K. Sustainability in real--time scheduling 2008 Journal of Computing Science and Engineering (JCSE)
Vol. 2(1), pp. 74-97 
article URL 
Abstract: A scheduling policy or a schedulability test is defined to be sustainable if any task system determined to be schedulable remains so if it behaves ‘‘better’’ than mandated by its system specifications. We provide a formal definition of sustainability, and subject the concept to systematic analysis in the context of the uniprocessor scheduling of periodic and sporadic task systems. We argue that it is, in general, preferable engineering practice to use sustainable tests if possible, and classify common uniprocessor schedulability tests according to whether they are sustainable or not.
BibTeX:
@article{Burns2008,
  author = {Burns, Alan and Baruah, Sanjoy K.},
  title = {Sustainability in real--time scheduling},
  journal = {Journal of Computing Science and Engineering (JCSE)},
  year = {2008},
  volume = {2},
  number = {1},
  pages = {74--97},
  url = {papers/Burns2008.pdf}
}
Burns, A. and Chen, Y. Implementing Transactions in a Distributed Real--Time System without Global Time 2009 Proceedings of the Work--in-Progress Session of the 30th IEEE Real-Time Systems Symposium (WiP RTSS), pp. 75-76  inproceedings URL 
Abstract: A simple algorithm is presented for implementing and analysing real--time transactions executing on a distributed platform. The algorithm does not require global time, but does not suffer from excessive jitter.
BibTeX:
@inproceedings{Burns2009,
  author = {Burns, Alan and Chen, Y.},
  title = {Implementing Transactions in a Distributed Real--Time System without Global Time},
  booktitle = {Proceedings of the Work--in-Progress Session of the 30th IEEE Real-Time Systems Symposium (WiP RTSS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {75--76},
  url = {papers/RTSS09WiPproceedings.pdf}
}
Burns, A. and Davis, R.I. Mixed Criticality Systems - A Review 2016   unpublished URL 
Abstract: This review covers research on the topic of mixed criticality systems that has been published since Vestal’s 2007 paper. It covers the period up to and including December 2015. The review is organised into the following topics: introduction and motivation, models, single processor analysis (including job-based, hard and soft tasks, fixed priority and EDF scheduling, shared resources and static and synchronous scheduling), multiprocessor analysis, related topics, realistic models, formal treatments, and systems issues. An appendix lists funded projects in the area of mixed criticality.
BibTeX:
@unpublished{Burns2016,
  author = {Burns, Alan and Davis, Robert Ian},
  title = {Mixed Criticality Systems - A Review},
  year = {2016},
  url = {https://www-users.cs.york.ac.uk/burns/review.pdf}
}
Burns, A. and Davis, R.I. Adaptive Mixed Criticality Scheduling with Deferred Preemption 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 21-30  inproceedings DOI URL 
Abstract: Adaptive Mixed Criticality (AMC) scheduling has previously been shown to be the most effective fixed priority approach for scheduling mixed criticality systems, while the idea of final non--preemptive regions has been shown to improve the schedulability of systems with a single criticality level. In this paper, we combine AMC with the concept of non-preemptive regions by making the final part of each task’s execution at each criticality level non-preemptive. We derive schedulability analysis for this approach, and provide an effective algorithm for choosing each task’s priority and the durations of its non-preemptive regions. Evaluations illustrate the benefits of this approach in terms of increased schedulability.
BibTeX:
@inproceedings{Burns2014,
  author = {Burns, Alan and Davis, Robert Ian},
  title = {Adaptive Mixed Criticality Scheduling with Deferred Preemption},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {21--30},
  url = {papers/Burns2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.12}
}
Burns, A. and Davis, R.I. Mixed Criticality Systems -- A Review 2013 School: University of York  techreport URL 
Abstract: This review covers research on the topic of mixed criticality systems that has been published since Vestal’s 2007 paper. It covers the period up to and including December 2013. The review is organised into the following topics: introduction and motivation, models, single processor analysis (including job--based, hard and soft tasks, fixed priority tasks, EDF, shared resources and static and synchronous scheduling), multiprocessor analysis, hierarchical scheduling, formal treatments, systems issues and funded projects in the area of mixed criticality.
BibTeX:
@techreport{Burns2013a,
  author = {Burns, Alan and Davis, Robert Ian},
  title = {Mixed Criticality Systems -- A Review},
  school = {University of York},
  year = {2013},
  url = {papers/Burns2013a.pdf}
}
Burns, A., Davis, R.I. and Punnekkat, S. Feasibility Anlaysis of Fault--Tolerant Real-Time Task Sets 1996 Proceedings of the 8th Euromicro Workshop on Real--Time Systems (EWRTS), pp. 29-33  inproceedings DOI URL 
Abstract: Many safety critical real--time systems, employ fault tolerant strategies in order to provide predictable performance in the presence of failures. One technique commonly employed is time redundancy using retry/re-execution of tasks. This can in turn affect the correctness of the system by causing deadlines to be missed. This paper provides exact schedulability tests for fault tolerant task sets under specified failure hypothesis.
BibTeX:
@inproceedings{Burns1996,
  author = {Burns, Alan and Davis, Robert Ian and Punnekkat, Sasikumar},
  title = {Feasibility Anlaysis of Fault--Tolerant Real-Time Task Sets},
  booktitle = {Proceedings of the 8th Euromicro Workshop on Real--Time Systems (EWRTS)},
  publisher = {IEEE Computer Society},
  year = {1996},
  pages = {29--33},
  url = {papers/Burns1996.pdf},
  doi = {http://doi.org/10.1109/EMWRTS.1996.557785}
}
Burns, A., Harbin, J. and Indrusiak, L.S. A Wormhole NoC Protocol for Mixed Criticality Systems 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 184-195  inproceedings DOI URL 
Abstract: Lack of scalability and difficulties in predicting the temporal behaviour of bus--based architectures has lead to the development of Network-on-Chip (NoC) protocols that provide a schedulable resource for moving data across multi-core platforms. Wormhole switching and credit-based flow control protocols have been used to support flit-level priority-preemptive link arbitration in NoCs, which leads to analysable temporal behaviour. In this paper we develop a new protocol (WPMC), based on the same family of protocols, that gives full support to mixed-criticality on-chip communications. WPMC is defined to give adequate partitioning between criticality levels, and to use resources efficiently. Analysis is developed and implementation aspects are considered. A cycle accurate simulator is used for scenario-based verification, and the effectiveness of the protocol and its scheduling model is evaluated via message-set generation.
BibTeX:
@inproceedings{Burns2014a,
  author = {Burns, Alan and Harbin, James and Indrusiak, Leandro Soares},
  title = {A Wormhole NoC Protocol for Mixed Criticality Systems},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {184--195},
  url = {papers/Burns2014a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.13}
}
Burns, A. and Wellings, A.J. A Schedulability Compatible Multiprocessor Resource Sharing Protocol -- MrsP 2013 Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS), pp. 282-291  inproceedings URL 
Abstract: Lock--based resource sharing protocols for single processor systems are well understood and supported in programming languages and in Real-Time Operating Systems. In contrast, multiprocessor resource sharing protocols are less well developed with no agreed best practice. In this paper we propose a new multiprocessor variant of a protocol based on the single processor priority ceiling protocol. The distinctive nature of the new protocol is that tasks waiting to gain access to a resource must service the resource on behalf of other tasks that are waiting for the same resource (but have been preempted). The form of the protocol is motivated by the desire to link the protocol with effective schedulability analysis. The protocol is general purpose, but is developed in this paper for partitioned fixed priority systems with the sporadic task model. Two methods of supporting the protocol are described, as is a prototype ‘proof of concept’ implementation for one of these schemes.
BibTeX:
@inproceedings{Burns2013,
  author = {Burns, Alan and Wellings, Andy J.},
  title = {A Schedulability Compatible Multiprocessor Resource Sharing Protocol -- MrsP},
  booktitle = {Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2013},
  pages = {282--291},
  url = {papers/Burns2013.pdf}
}
Buttazzo, G.C. Hard Real--Time Computing Systems: Predictable Scheduling Algorithms and Applications (3rd Edition) 2011
Vol. 24, pp. 521 
book URL 
Abstract: This updated edition offers an indispensable exposition on real--time computing, with particular emphasis on predictable scheduling algorithms. It introduces the fundamental concepts of real-time computing, demonstrates the most significant results in the field, and provides the essential methodologies for designing predictable computing systems used to support time-critical control applications. Along with an in-depth guide to the available approaches for the implementation and analysis of real-time applications, this revised edition contains a close examination of recent developments in real-time systems, including limited preemptive scheduling, resource reservation techniques, overload handling algorithms, and adaptive scheduling techniques. This volume serves as a fundamental advanced-level textbook. Each chapter provides basic concepts, which are followed by algorithms, illustrated with concrete examples, figures and tables. Exercises and solutions are provided to enhance self-study, making this an excellent reference for those interested in real-time computing for designing and/or developing predictable control applications.
BibTeX:
@book{Buttazzo2011,
  author = {Buttazzo, Giorgio C.},
  title = {Hard Real--Time Computing Systems: Predictable Scheduling Algorithms and Applications (3rd Edition)},
  publisher = {Springer},
  year = {2011},
  volume = {24},
  pages = {521},
  url = {papers/Buttazzo2011.pdf}
}
Buttazzo, G.C. Rate Monotonic vs. EDF: Judgment Day 2005 Real-Time Systems
Vol. 29(1), pp. 5-26 
article DOI URL 
Abstract: Since the first results published in 1973 by Liu and Layland on the Rate Monotonic (RM) and Earliest Deadline First (EDF) algorithms, a lot of progress has been made in the schedulability analysis of periodic task sets. Unfortunately, many misconceptions still exist about the properties of these two scheduling methods, which usually tend to favor RM more than EDF. Typical wrong statements often heard in technical conferences and even in research papers claim that RM is easier to analyze than EDF, it introduces less runtime overhead, it is more predictable in overload conditions, and causes less jitter in task execution.

Since the above statements are either wrong, or not precise, it is time to clarify these issues in a systematic fashion, because the use of EDF allows a better exploitation of the available resources and significantly improves system's performance.

This paper compares RM against EDF under several aspects, using existing theoretical results, specific simulation experiments, or simple counterexamples to show that many common beliefs are either false or only restricted to specific situations.

BibTeX:
@article{Buttazzo2005,
  author = {Buttazzo, Giorgio C.},
  title = {Rate Monotonic vs. EDF: Judgment Day},
  journal = {Real-Time Systems},
  year = {2005},
  volume = {29},
  number = {1},
  pages = {5--26},
  url = {papers/Buttazzo2005.pdf},
  doi = {http://doi.org/10.1023/B:TIME.0000048932.30002.d9}
}
Buttazzo, G.C., Lipari, G., Caccamo, M. and Abeni, L. Elastic scheduling for flexible workload management 2002 IEEE Transactions on Computers
Vol. 51(3), pp. 289-302 
article DOI URL 
Abstract: An increasing number of real--time applications related to multimedia and adaptive control systems require greater flexibility than classical real-time theory usually permits. We present a novel scheduling framework in which tasks are treated as springs with given elastic coefficients to better conform to the actual load conditions. Under this model, periodic tasks can intentionally change their execution rate to provide different quality of service and the other tasks can automatically adapt their periods to keep the system underloaded. The proposed model can also be used to handle overload conditions in a more flexible way and to provide a simple and efficient mechanism for controlling a system's performance as a function of the current load.
BibTeX:
@article{Buttazzo2002,
  author = {Buttazzo, Giorgio C. and Lipari, Giuseppe and Caccamo, Marco and Abeni, Luca},
  title = {Elastic scheduling for flexible workload management},
  journal = {IEEE Transactions on Computers},
  year = {2002},
  volume = {51},
  number = {3},
  pages = {289--302},
  url = {papers/Buttazzo2002.pdf},
  doi = {http://doi.org/10.1109/12.990127}
}
Buttazzo, G.C. and Stankovic, J.A. RED: Robust Earliest Deadline Scheduling 1993 (UM-CS-1993-025)School: University of Massachusetts  techreport URL 
Abstract: In this paper we introduce a robust earlist deadline scheduling algorithm for dealing with sporadic tasks under overloads in a hard real--time environment. The algorithm synergestically combines many features including a very important minimum level of guarantee, dynamic guarantees, graceful degredation in overloads, deadline tolerance, resource reclaiming, and dynamic re-guarantees. A necessary and sufficient schedulability test is presented, and an efficient 0(n) guarantee algorithm is proposed. The new algorithm is evaluated via simulation and compared to several baseline algorithms. The experimental results show excellant performance of the new algorithm in normal and overload conditions.
BibTeX:
@techreport{Buttazzo1993,
  author = {Buttazzo, Giorgio C. and Stankovic, John A.},
  title = {RED: Robust Earliest Deadline Scheduling},
  school = {University of Massachusetts},
  year = {1993},
  number = {UM--CS-1993-025},
  url = {papers/Buttazzo1993.pdf}
}
Campbell, B. and Dutta, P. Gemini: A Non--invasive, Energy-Harvesting True Power Meter 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 324-333  inproceedings DOI URL 
Abstract: Power meters are critical for submetering loads in residential and commercial settings, but high installation cost and complexity hamper their broader adoption. Recent approaches address installation burdens by proposing non--invasive meters that easily clip onto a wire, or stick onto a circuit breaker, to perform contactless metering. Unfortunately, these designs require regular maintenance (e.g. battery replacement) or reduce measurement accuracy (e.g. work poorly with non-unity power factors). This paper presents Gemini, a new design point in the power metering space. Gemini addresses the drawbacks of prior approaches by decoupling and distributing the AC voltage and current measurement acquisitions, and recombining them wirelessly using a low-bandwidth approach, to offer non-invasive real, reactive, and apparent power metering. Battery maintenance is eliminated by using an energy-harvesting design that enables the meter to power itself using a current transformer. Accuracy is substantially improved over other non-invasive meters by virtualizing the voltage channel—effectively allowing the meter to calculate power as if it could directly measure voltage (since true power requires sample-by-sample multiplication of current and voltage measurements acquired with tight timing constraints). Collectively, these improvements result in a new design point that meters resistive loads with 0.6 W average error and a range of reactive and switching loads with 2.2 W average error—matching commercial, mains-powered solutions.
BibTeX:
@inproceedings{Campbell2014,
  author = {Campbell, Bradford and Dutta, Prabal},
  title = {Gemini: A Non--invasive, Energy-Harvesting True Power Meter},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {324--333},
  url = {papers/Campbell2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.36}
}
Carpenter, J., Funk, S.H., Holman, P., Srinivasan, A., Anderson, J.H. and Baruah, S.K. A Categorization of Real--Time Multiprocessor Scheduling Problems and Algorithms 2004 Handbook of Scheduling: Algorithms, Models, and Performance Analysis  incollection URL 
BibTeX:
@incollection{Carpenter2004,
  author = {Carpenter, John and Funk, Shelby Hyatt and Holman, P. and Srinivasan, A. and Anderson, James H. and Baruah, Sanjoy K.},
  title = {A Categorization of Real--Time Multiprocessor Scheduling Problems and Algorithms},
  booktitle = {Handbook of Scheduling: Algorithms, Models, and Performance Analysis},
  publisher = {Chapman and Hall/CRC},
  year = {2004},
  url = {papers/Carpenter2004.pdf}
}
Cerqueira, F., Gujarati, A. and Brandenburg, B.B. Linux's Processor Affinity API, Refined: Shifting Real--Time Tasks Towards Higher Schedulability 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 249-259  inproceedings DOI URL 
Abstract: Virtually all major real--time operating systems such as QNX, VxWorks, LynxOS, and most real-time variants of Linux expose processor affinity APIs to restrict task migrations. Initially motivated by throughput and isolation reasons, the ability to flexibly control migrations on a per-task basis has also proved to be useful from a schedulability perspective.
However, as the motivation to use processor affinities is highly application--specific, the two interests can conflict, i.e., the fixed, user-specified processor affinities chosen for non-schedulability reasons can actually limit any possible gains in schedulability. This paper specifically addresses the scenario where processor affinities are given as input, and investigates the following question: while maintaining API compatibility (i.e., without changing the interface exposed to the programmer), is it possible to improve schedulability beyond what Linux and Linux-like systems currently offer, without violating the original affinity restrictions?
To answer this question, we explore the similarities between priority--based scheduling with processor affinities and the assignment problem with seniority and job priority constraints, studied previously by Caron et al. in an operations-research context, to derive a more generic model of migrations. Based on vertex-weighted bipartite matchings, the proposed model exploits the idea of shifting high-priority tasks among processors in their affinity set, in order to accommodate lower-priority tasks that have more constrained processor affinities. The proposed approach is analyzed with a novel shifting-aware schedulability analysis based on linear programming. An empirical evaluation in terms of schedulability shows shifting to be effective, although performance naturally degrades if migration overheads are high.
BibTeX:
@inproceedings{Cerqueira2014,
  author = {Cerqueira, Felipe and Gujarati, Arpan and Brandenburg, Björn B.},
  title = {Linux's Processor Affinity API, Refined: Shifting Real--Time Tasks Towards Higher Schedulability},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {249--259},
  url = {papers/Cerqueira2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.29}
}
Chabrol, D., David, V., Aussaguès, C., Louise, S. and Daumas, F. Deterministic Distributed Safety--Critical Real-Time Systems within the OASIS Approach 2005 Proceedings of the 17th IASTED International Conference on Parallel and Distributed Computing and Systems (PDCS), pp. 9  inproceedings URL 
Abstract: Distributed real--time systems have found widespread use in most key industries (nuclear, avionics, automotive, etc). This trend continues, with increasingly intricate systems performing safety-critical functions. Given the current emphasis on system reliability, major efforts must be devoted to demonstrating and guaranteeing their safety. OASIS provides a real-time multitasking and communication approach with a complete set of development tools (e.g. code generation, validation, simulation and execution) to facilitate the design, testing and validation stages complying with prevailing standards. OASIS is specifically geared to building deterministic systems whose behavior is predictable and reproducible in both the logical and temporal domains. Its development package is industrially available for single processor architectures and is presently being qualified for 1E-class nuclear systems. This paper describes our research, which focuses on implementing distributed safety-critical real-time systems.
BibTeX:
@inproceedings{Chabrol2005,
  author = {Chabrol, Damien and David, Vincent and Aussaguès, Christophe and Louise, Stéphane and Daumas, Frédéric},
  title = {Deterministic Distributed Safety--Critical Real-Time Systems within the OASIS Approach},
  booktitle = {Proceedings of the 17th IASTED International Conference on Parallel and Distributed Computing and Systems (PDCS)},
  publisher = {Acta Press},
  year = {2005},
  pages = {9},
  url = {papers/Chabrol2005.pdf}
}
Chandarli, Y. Real-time Scheduling for Energy-Harvesting Embedded Systems 2014 School: Université Paris-Est  phdthesis  
BibTeX:
@phdthesis{Chandarli2014,
  author = {Chandarli, Younès},
  title = {Real-time Scheduling for Energy-Harvesting Embedded Systems},
  school = {Université Paris-Est},
  year = {2014}
}
Chandarli, Y., Fauberteau, F., Damien, M., Midonnet, S. and Qamhieh, M. YARTISS: A Tool to Visualize, Test, Compare and Evaluate Real--Time Scheduling Algorithms 2012 Proceedings of the 3rd International Workshop on Analysis Tools and Methodologies for Embedded and Real--time Systems (WATERS)  inproceedings  
BibTeX:
@inproceedings{Chandarli2012,
  author = {Chandarli, Younès and Fauberteau, Frédéric and Masson Damien and Midonnet, Serge and Qamhieh, Manar},
  title = {YARTISS: A Tool to Visualize, Test, Compare and Evaluate Real--Time Scheduling Algorithms},
  booktitle = {Proceedings of the 3rd International Workshop on Analysis Tools and Methodologies for Embedded and Real--time Systems (WATERS)},
  year = {2012},
  note = {http://yartiss.univ--mlv.fr/}
}
Chang, W., Pröbstl, A., Goswami, D., Zamani, M. and Chakraborty, S. Battery-- and Aging-Aware Embedded Control Systems for Electric Vehicles 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 238-248  inproceedings DOI URL 
Abstract: In this paper, for the first time, we propose a battery-- and aging-aware optimization framework for embedded control systems design in electric vehicles (EVs). Performance and reliability of an EV are influenced by feedback control loops implemented into in-vehicle electrical/electronic (E/E) architecture. In this context, we consider the following design aspects of an EV: (i) battery usage; (ii) processor aging of the in-vehicle embedded platform. In this work, we propose a design optimization framework for embedded controllers with gradient-based and stochastic methods taking into account quality of control (QoC), battery usage and processor aging. First, we obtain a Pareto front between QoC and battery usage utilizing the optimization framework. Well-distributed non-dominated solutions are achieved by solving a constrained bi-objective optimization problem. In general, QoC of a control loop highly depends on the sampling period. When the processor ages, on-chip monitors could be used to measure the delay of the critical path, based on which, the processor operating frequency is reduced to ensure correct functioning. As a result, the sampling period gets longer opening up the possibility of QoC deterioration, which is highly undesirable for safety-critical applications in EVs. Utilizing the proposed framework, we take into account the effect of processor aging by re-optimizing the controller design with the prolonged sampling period resulting from processor aging. We illustrate the approach considering electric motor control in EVs. Our experimental results show that the effect of processor aging on QoC deterioration can be mitigated by controller re-optimization with a slight compromise on battery usage.
BibTeX:
@inproceedings{Chang2014,
  author = {Chang, Wanli and Pröbstl, Alma and Goswami, Dip and Zamani, Majid and Chakraborty, Samarjit},
  title = {Battery-- and Aging-Aware Embedded Control Systems for Electric Vehicles},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {238--248},
  url = {papers/Chang2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.24}
}
Chantem, T., Dick, R.P. and Hu, X.S. Temperature--Aware Scheduling and Assignment for Hard Real-Time Applications on MPSoCs 2008 Proceedings of the Design, Automation and Test in Europe (DATE), pp. 288-293  inproceedings DOI URL 
Abstract: Thermal effects in MPSoCs may cause the violation of timing constraints in real--time systems. This paper presents a mixed integer linear programming based solution to this problem. Tasks are assigned and scheduled to an MPSoC to minimize peak temperature, subject to real-time constraints. The proposed approach outperforms existing methods, reducing peak temperature by up to 24.66°C and by an average of 8.75°C when compared to minimal-energy solutions. We also present a heuristic for use on large problem instances. Steady-state thermal analysis is used for tasks with long execution times compared to the RC thermal time constants of the cores. Transient analysis is used otherwise. The steady-state analysis based heuristic finds solutions with at most 3.40°C deviation from optimal peak temperature (0.22°C on average) while improving upon existing technique by as much as 25.71°C and 10.86°C on average. The transient analysis based heuristic further reduce peak temperature by 1°C in the best case and 0.17°C on average.
BibTeX:
@inproceedings{Chantem2008,
  author = {Chantem, Thidapat and Dick, Robert P. and Hu, X. Sharon},
  title = {Temperature--Aware Scheduling and Assignment for Hard Real-Time Applications on MPSoCs},
  booktitle = {Proceedings of the Design, Automation and Test in Europe (DATE)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {288--293},
  url = {papers/Chantem2008.pdf},
  doi = {http://doi.org/10.1109/DATE.2008.4484694}
}
Chantem, T., Hu, X.S. and Dick, R.P. Temperature--Aware Scheduling and Assignment for Hard Real-Time Applications on MPSoCs 2011 IEEE Transactions on Very Large Scale Integration Systems (VLSI)
Vol. 19(10), pp. 1884-1897 
article DOI URL 
Abstract: Increasing integrated circuit (IC) power densities and temperatures may hamper multiprocessor system--on-chip (MPSoC) use in hard real-time systems. This paper formalizes the temperature-aware real-time MPSoC assignment and scheduling problem and presents an optimal phased steady-state mixed integer linear programming-based solution that considers the impact of scheduling and assignment decisions on MPSoC thermal profiles to directly minimize the chip peak temperature. We also introduce a flexible heuristic framework for task assignment and scheduling that permits system designers to trade off accuracy for running time when solving large problem instances. Finally, for task sets with sufficient slack, we show that inserting idle times between task executions can further reduce the peak temperature of the MPSoC quite significantly.
BibTeX:
@article{Chantem2011,
  author = {Chantem, Thidapat and Hu, X. Sharon and Dick, Robert P.},
  title = {Temperature--Aware Scheduling and Assignment for Hard Real-Time Applications on MPSoCs},
  journal = {IEEE Transactions on Very Large Scale Integration Systems (VLSI)},
  year = {2011},
  volume = {19},
  number = {10},
  pages = {1884--1897},
  url = {papers/Chantem2011.pdf},
  doi = {http://doi.org/10.1109/TVLSI.2010.2058873}
}
Chantem, T., Hu, X.S. and Dick, R.P. Temperature--Aware Scheduling and Assignment for Hard Real-Time Applications on MPSoCs 2011 IEEE Transactions on Very Large Scale Integration Systems (VLSI)
Vol. 19(10), pp. 1884-1897 
article DOI URL 
Abstract: Increasing integrated circuit (IC) power densities and temperatures may hamper multiprocessor system--on-chip (MPSoC) use in hard real-time systems. This paper formalizes the temperature-aware real-time MPSoC assignment and scheduling problem and presents an optimal phased steady-state mixed integer linear programming-based solution that considers the impact of scheduling and assignment decisions on MPSoC thermal profiles to directly minimize the chip peak temperature. We also introduce a flexible heuristic framework for task assignment and scheduling that permits system designers to trade off accuracy for running time when solving large problem instances. Finally, for task sets with sufficient slack, we show that inserting idle times between task executions can further reduce the peak temperature of the MPSoC quite significantly.
BibTeX:
@article{Chantem2011a,
  author = {Chantem, Thidapat and Hu, X. Sharon and Dick, Robert P.},
  title = {Temperature--Aware Scheduling and Assignment for Hard Real-Time Applications on MPSoCs},
  journal = {IEEE Transactions on Very Large Scale Integration Systems (VLSI)},
  year = {2011},
  volume = {19},
  number = {10},
  pages = {1884--1897},
  url = {papers/Chantem2011.pdf},
  doi = {http://doi.org/10.1109/TVLSI.2010.2058873}
}
Charara, H., Schabarg, J.-L., Ermont, J. and Fraboul, C. Methods for bounding end--to-end delays on an AFDX network 2006 Proceedings of the 18th Euromicro Conference on Real--Time Systems (ECRTS)  inproceedings  
BibTeX:
@inproceedings{Charara2006,
  author = {Charara, Hussein and Schabarg, Jean--Luc and Ermont, Jérôme and Fraboul, Christian},
  title = {Methods for bounding end--to-end delays on an AFDX network},
  booktitle = {Proceedings of the 18th Euromicro Conference on Real--Time Systems (ECRTS)},
  year = {2006}
}
Chatterjee, K., Pavlogiannis, A., Kößler, A. and Schmid, U. A Framework for Automated Competitive Analysis of On--line Scheduling of Firm-Deadline Tasks 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 118-127  inproceedings DOI URL 
Abstract: We present a flexible framework for the automated competitive analysis of on--line scheduling algorithms for firm-deadline real-time tasks based on multi-objective graphs: Given a taskset and an on-line scheduling algorithm specified as a labeled transition system, along with some optional safety, liveness, and/or limit-average constraints for the adversary, we automatically compute the competitive ratio of the algorithm w.r.t. a clairvoyant scheduler. We demonstrate the flexibility and power of our approach by comparing the competitive ratio of several on-line algorithms, including D over , that have been proposed in the past, for various tasksets. Our experimental results reveal that none of these algorithms is universally optimal, in the sense that there are tasksets where other schedulers provide better performance. Our framework is hence a very useful design tool for selecting optimal algorithms for a given application.
BibTeX:
@inproceedings{Chatterjee2014,
  author = {Chatterjee, Krishnendu and Pavlogiannis, Andreas and Kößler, Alexander and Schmid, Ulrich},
  title = {A Framework for Automated Competitive Analysis of On--line Scheduling of Firm-Deadline Tasks},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {118--127},
  url = {papers/Chatterjee2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.9}
}
Chen, C.-M. and Tripathi, S.K. Multiprocessor Priority Ceiling Based Protocols 1994 (3252)School: University of Maryland  techreport URL 
Abstract: We study resource synchronization in multiprocessor hard real--time systems. Specifically, we propose a multiprocessor resource control protocol which allows a job to simultaneously lock multiple global resources, removing a restriction from previous protocols. Allowing nested critical sections may permit a ner granularity of synchronization, increasing parallelism and throughput. All the protocols discussed belong to the class of priority inheritance protocols and rely in some fashion on priority ceilings for global semaphores. We consider both static and dynamic priorities, building upon the multiprocessor priority ceiling protocol (MPCP) proposed by Rajkumar et al. and the dynamic priority ceiling protocol (DPCP) proposed by Chen and Lin. The extended protocols prevent deadlock and transitive blocking. We derive bounds for worse case blocking time, and describe su cient conditions to guarantee that m sets of periodic tasks can be scheduled on an m multiprocessor system. Performance comparisons of these protocols with MPCP shows that the proposed protocols increase schedulability
BibTeX:
@techreport{Chen1994,
  author = {Chen, Chia--Mei and Tripathi, Satish K.},
  title = {Multiprocessor Priority Ceiling Based Protocols},
  school = {University of Maryland},
  year = {1994},
  number = {3252},
  url = {papers/Chen1994.pdf}
}
Chen, J., Tan, R., Xing, G. and Wang, X. PTEC: A System for Predictive Thermal and Energy Control in Data Centers 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 218-227  inproceedings DOI URL 
BibTeX:
@inproceedings{Chen2014a,
  author = {Chen, Jinzhu and Tan, Rui and Xing, Guoliang and Wang, Xiaorui},
  title = {PTEC: A System for Predictive Thermal and Energy Control in Data Centers},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {218--227},
  url = {papers/Chen2014a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.27}
}
Chen, J.-J. and Liu, C. Fixed--Relative-Deadline Scheduling of Hard Real-Time Tasks with Self-Suspensions 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 149-160  inproceedings DOI URL 
Abstract: In many real--time systems, tasks may experience self-suspension delays when accessing external devices. The problem of scheduling such self-suspending tasks to meet hard deadlines on a uniprocessor is known to be N P-hard in the strong sense. Current solutions including the common suspension-oblivious approach of treating all suspensions as computation can be quite pessimistic. This paper shows that another category of scheduling algorithms, namely fixed-relative-deadline (FRD) scheduling, may yield better performance than classical schedulers such as EDF and RM, for real-time tasks that may experience one self-suspension during the execution of a task instance. We analyze a simple FRD algorithm, namely EDA, and derive corresponding pseudo-polynomial-time and linear-time schedulability tests. To analyze the quality of EDA and its schedulability tests, we analyze their resource augmentation factors, with respect to the speed-up factor that is needed to ensure the schedulability and feasibility of the resulting schedule. Specifically, the speed-up factor of EDA is 2 and 3, when referring to the optimal FRD scheduling and any feasible arbitrary scheduling, respectively. Moreover, the speed-up factor of the proposed linear-time schedulability test is 2.787 and 4.875, when referring to the optimal FRD scheduling and any feasible arbitrary scheduling, respectively. Furthermore, extensive experiments presented herein show that our proposed linear-time schedulability test improves upon prior approaches by a significant margin. To our best knowledge, for the scheduling of self-suspending tasks, these are the first results of any sort that indicate it might be possible to design good approximation algorithms.
BibTeX:
@inproceedings{Chen2014,
  author = {Chen, Jian--Jia and Liu, Cong},
  title = {Fixed--Relative-Deadline Scheduling of Hard Real-Time Tasks with Self-Suspensions},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {149--160},
  url = {papers/Chen2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.31}
}
Chen, M.-I. and Lin, K.-J. Dynamic Priority Ceilings: A Concurrency Control Protocol for Real--Time Systems 1990 Real--Time Systems
Vol. 2(4), pp. 325-346 
article DOI URL 
Abstract: Real--time systems have stringent deadline requirements for their tasks. To meet the requirements, a real-time system must use scheduling algorithms that ensure a predictable response even in the face of mutually exclusive accesses to critical sections. We present a concurrency control protocol for systems using the earliest deadline first scheduling algorithm. The protocol specifies a dynamic priority ceiling for each critical section which is the earliest deadline of jobs which are currently in or will enter the critical section. Jobs trying to enter a critical section will be blocked if they do not have a priority higher than the priority ceiling of any critical section which is in use. We show that the protocol prevents both deadlock and chained blocking. The schedulability condition and implementation issues of the protocol are also discussed.
BibTeX:
@article{Chen1990,
  author = {Chen, Min--Ih and Lin, Kwei-Jay},
  title = {Dynamic Priority Ceilings: A Concurrency Control Protocol for Real--Time Systems},
  journal = {Real--Time Systems},
  year = {1990},
  volume = {2},
  number = {4},
  pages = {325--346},
  url = {papers/Chen1990.pdf},
  doi = {http://doi.org/10.1007/BF01995676}
}
Chéramy, M., Déplance, A.-M. and Hladik, P.-E. Simulation of real--time multiprocessor scheduling with overheads 2013 In proceedings of SIMULTECH  inproceedings  
BibTeX:
@inproceedings{Cheramy2013,
  author = {Chéramy, Maxime and Déplance, Anne--Marie and Hladik, Pierre-Emmanuel},
  title = {Simulation of real--time multiprocessor scheduling with overheads},
  booktitle = {In proceedings of SIMULTECH},
  year = {2013},
  note = {http://homepages.laas.fr/mcheramy/simso/}
}
Chetto, H. and Chetto, M. Some Results of the Earliest Deadline Scheduling Algorithm 1989 IEEE Transactions on Software Engineering
Vol. 15(10), pp. 1261-1269 
article DOI URL 
Abstract: Task scheduling is an important issue in the design of a real--time computer system because tasks have execution deadlines that must be met, otherwise the system fails with severe consequences upon the environment. In this paper, we study the problem of scheduling periodic time critical tasks on a monoprocessor system. A periodic time critical task consists of an infinite number of requests, each of which has a prescribed deadline. Tasks are assumed to meet their timing requirements when scheduled by the Earliest Deadline algorithm and preemptions are allowed. We report results from some investigations into the problem of making optimum use of the remaining processor idle time in scheduling period tasks either as soon as possible or as late as possible. The major results consist of the statement and proof of properties relating to localization and duration of idle time intervals and enable us to provide an efficient algorithm for determining maximum quantity of total idle time availble between any two instants. We describe how these results can be applied, first to the decision problem that arises when a sporadic time critical tasks occurs and requires to be run at an unpredictable time and second, to the scheduling problem that arises in a fault tolerant system using the deadline mechanism for which each task implements primary and alternate algorithms.
BibTeX:
@article{Chetto1989,
  author = {Chetto, Houssine and Chetto, Maryline},
  title = {Some Results of the Earliest Deadline Scheduling Algorithm},
  journal = {IEEE Transactions on Software Engineering},
  year = {1989},
  volume = {15},
  number = {10},
  pages = {1261--1269},
  url = {papers/Chetto1989.pdf},
  doi = {http://doi.org/10.1109/TSE.1989.559777}
}
Chetto, M., Masson, D. and Midonnet, S. Fixed Priority Scheduling Strategies for Ambient Energy--Harvesting Embedded Systems 2011 Proceedings of the IEEE/ACM International Conference on Green Computing and Communications (GreenCom), pp. 50-55  inproceedings DOI URL 
Abstract: The new generation of embedded systems will have the capability to harvest energy from the environment. The electrical energy which is available to power these devices changes over time and is limited by the size of the energy storage unit such as battery or capacitor and the size of the harvester such as a solar panel. In order to cope with this limitation, the system has to dynamically decide when to be active and when to sleep in order to provide the best quality of service without wasting the harvested energy. In this paper, we study this problem for a uniprocessor architecture where periodic tasks have to execute with deadline constraints according to a preemptive fixed priority rule. We evaluate and compare several scheduling approaches by means of simulation.
BibTeX:
@inproceedings{Chetto2011,
  author = {Chetto, Maryline and Masson, Damien and Midonnet, Serge},
  title = {Fixed Priority Scheduling Strategies for Ambient Energy--Harvesting Embedded Systems},
  booktitle = {Proceedings of the IEEE/ACM International Conference on Green Computing and Communications (GreenCom)},
  publisher = {IEEE Computer Society / ACM Computer Press},
  year = {2011},
  pages = {50--55},
  url = {papers/Chetto2011.pdf},
  doi = {http://doi.org/10.1109/GreenCom.2011.17}
}
Chillet, D., Eiche, A., Pillement, S. and Sentieys, O. Real--time scheduling on heterogeneous system-on-chip architectures using an optimised artificial neural network 2011 Journal of Systems Architecture
Vol. 57(4), pp. 340-353 
article DOI URL 
BibTeX:
@article{Chillet2011,
  author = {Daniel Chillet and Antoine Eiche and Sébastien Pillement and Olivier Sentieys},
  title = {Real--time scheduling on heterogeneous system-on-chip architectures using an optimised artificial neural network},
  journal = {Journal of Systems Architecture},
  year = {2011},
  volume = {57},
  number = {4},
  pages = {340--353},
  url = {papers/Chillet2011.pdf},
  doi = {http://doi.org/10.1016/j.sysarc.2011.01.004}
}
Chillet, D., Pillement, S. and Sentieys, O. A Neural Network Model for Real--Time Scheduling on Heterogeneous SoC Architectures 2007 Proceedings of 20th International Joint Conference on Neural Networks (IJCNN), pp. 102-107  inproceedings DOI URL 
Abstract: With increasing embedded application complexity, designers have proposed to introduce new hardware architectures based on heterogeneous processing units on a single chip. For these architectures, the scheduling service of a realtime operating system must be able to assign tasks on different execution resources. This paper presents a model of artificial neural networks used for real--time task scheduling to heterogeneous system-on-chip architectures. Our proposition is an adaptation of the Hopfield model and the main objective concerns the minimization of the neuron number to facilitate future hardware implementation of this service. In fact, to ensure rapid convergence and low complexity, this number must be dramatically reduced. So, we propose new constructing rules to design smaller neural network and we show, through simulations, that network stabilization is obtained without reinitialisation of the network.
BibTeX:
@inproceedings{Chillet2007,
  author = {Chillet, Daniel and Pillement, Sébastien and Sentieys, Olivier},
  title = {A Neural Network Model for Real--Time Scheduling on Heterogeneous SoC Architectures},
  booktitle = {Proceedings of 20th International Joint Conference on Neural Networks (IJCNN)},
  publisher = {IEEE},
  year = {2007},
  pages = {102--107},
  url = {papers/Chillet2007.pdf},
  doi = {http://doi.org/10.1109/IJCNN.2007.4370938}
}
Cho, H., Ravindran, B. and Jensen, E.D. An Optimal Real--Time Scheduling Algorithm for Multiprocessors 2006 Proceedings of the 27th IEEE Real--Time Systems Symposium (RTSS), pp. 101-110  inproceedings DOI URL 
Abstract: We present an optimal real--time scheduling algorithm for multiprocessors — one that satisfies all task deadlines, when the total utilization demand does not exceed the utilization capacity of the processors. The algorithm called LLREF, is designed based on a novel abstraction for reasoning about task execution behavior on multiprocessors: the Time and Local Execution Time Domain Plane (or TL plane). LLREF is based on the fluid scheduling model and the fairness notion, and uses the T-L plane to describe fluid schedules without using time quanta, unlike the optimal Pfair algorithm (which uses time quanta). We show that scheduling for multiprocessors can be viewed as repeatedly occurring T-L planes, and feasibly scheduling on a single T-L plane results in the optimal schedule. We analytically establish the optimality of LLREF. Further, we establish that the algorithm has bounded overhead, and this bound is independent of time quanta (unlike Pfair). Our simulation results validate our analysis on the algorithm overhead.
BibTeX:
@inproceedings{Cho2006,
  author = {Cho, Hyeonjoong and Ravindran, Binoy and Jensen, E. Douglas},
  title = {An Optimal Real--Time Scheduling Algorithm for Multiprocessors},
  booktitle = {Proceedings of the 27th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {101--110},
  url = {papers/Cho2006.pdf},
  doi = {http://doi.org/10.1109/RTSS.2006.10}
}
Choquet-Geniet, A. and Fotsing, C. Linear transformation of conditional real--time tasks 2012 Proceedings of the 20th International Conference on Real--Time and Network (RTNS), pp. 201-210  inproceedings DOI URL 
Abstract: The classical schedulability theory generally considers linear tasks. Scheduling conditional task set is much more intricate. We thus propose a transformation of a conditional task set into a linear task set on which the traditional linear schedulability tools can be used. We prove that this transformation is consistent in the sense that a positive linear schedulability diagnosis is not misleading: if the linear task set is feasible, so was the conditional task set. But the converse does not hold.
BibTeX:
@inproceedings{Choquet--Geniet2012,
  author = {Choquet--Geniet, Annie and Fotsing, Christian},
  title = {Linear transformation of conditional real--time tasks},
  booktitle = {Proceedings of the 20th International Conference on Real--Time and Network (RTNS)},
  publisher = {ACM},
  year = {2012},
  pages = {201--210},
  url = {papers/Choquet--Geniet2012.pdf},
  doi = {http://doi.org/10.1145/2392987.2393013}
}
Coffman Jr., E.G., Garey, M.R. and Johnson, D.S. Approximation Algorithms for Bin Packing: A Survey 1996 Approximation Algorithms for NP--Hard Problems, pp. 46-93  incollection  
BibTeX:
@incollection{CoffmanJr.1996,
  author = {Coffman Jr., Edward G. and Garey, Mickael R. and Johnson, David S.},
  title = {Approximation Algorithms for Bin Packing: A Survey},
  booktitle = {Approximation Algorithms for NP--Hard Problems},
  publisher = {PWS Publishing Co.},
  year = {1996},
  pages = {46--93}
}
Colette, S., Cucu, L. and Goossens, J. Integrating job parallelism in real--time scheduling theory 2008 Information Processing Letters
Vol. 106(5), pp. 180-187 
article DOI URL 
Abstract: We investigate the global scheduling of sporadic, implicit deadline, real--time task systems on multiprocessor platforms. We provide a task model which integrates job parallelism. We prove that the time-complexity of the feasibility problem of these systems is linear relatively to the number of (sporadic) tasks for a fixed number of processors. We propose a scheduling algorithm theoretically optimal (i.e., preemptions and migrations neglected). Moreover, we provide an exact feasibility utilization bound. Lastly, we propose a technique to limit the number of migrations and preemptions.
BibTeX:
@article{Colette2008,
  author = {Colette, Sébastien and Cucu, Liliana and Goossens, Joël},
  title = {Integrating job parallelism in real--time scheduling theory},
  journal = {Information Processing Letters},
  year = {2008},
  volume = {106},
  number = {5},
  pages = {180--187},
  url = {papers/Colette2008.pdf},
  doi = {http://doi.org/10.1016/j.ipl.2007.11.014}
}
Colin, A. and Puaut, I. Worst--Case Execution Time Analysis of the RTEMS Real-Time Operating System 2001 Proceedings of the 13th Euromicro Conference on Real--time Systems (ECRTS), pp. 191-198  inproceedings DOI URL 
Abstract: An important issue in building operating systems for hard real--time applications is to compute the worst-case execution times (WCET) of the operating system activities. Traditionally, this has been achieved by an exhaustive testing of the operating system, with a careful attention on the testing conditions to reproduce the worst-case execution scenario. In this paper we explore the alternative approach of using static analysis to predict off-line the WCET of the system calls of a real-time kernel, the RTEMS kernel. We give qualitative and quantitative results on the analysis of RTEMS, and draw some conclusions on the extent to which static analysis can be used on operating system code.
BibTeX:
@inproceedings{Colin2001,
  author = {Colin, Antoine and Puaut, Isabelle},
  title = {Worst--Case Execution Time Analysis of the RTEMS Real-Time Operating System},
  booktitle = {Proceedings of the 13th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2001},
  pages = {191--198},
  url = {papers/Colin2001.pdf},
  doi = {http://doi.org/10.1109/EMRTS.2001.934029}
}
Corbalán, J., Martorell, X. and Labarta, J. Improving Gang Scheduling through Job Performance Analysis and Malleability 2001 Proceedings of the 15th International Conference on Supercomputing (ICS), pp. 303-311  inproceedings DOI URL 
Abstract: The OpenMP programming model provides parallel applications a very important feature: job malleability. Job malleability is the capacity of an application to dynamically adapt its parallelism to the number of processors allocated to it. We believe that job malleability provides to applications the flexibility that a system needs to achieve its maximum performance. We also defend that a system has to take its decisions not only based on user requirements but also based on run--time performance measurements to ensure the efficient use of resources. Job malleability is the application characteristic that makes possible the run-time performance analysis. Without malleability applications would not be able to adapt their parallelism to the system decisions. To support these ideas, we present two new approaches to attack the two main problems of Gang Scheduling: the excessive number of time slots and the fragmentation. Our first proposal is to apply a scheduling policy inside each time slot of Gang Scheduling to distribute processors among applications considering their efficiency, calculated based on run-time measurements. We call this policy Performance-Driven Gang Scheduling. Our second approach is a new re-packing algorithm, Compress&Join, that exploits the job malleability. This algorithm modifies the processor allocation of running applications to adapt it to the system necessities and minimize the fragmentation and number of time slots. These proposals have been implemented in a SGI Origin 2000 with 64 processors. Results show the validity and convenience of both, to consider the job performance analysis calculated at run-time to decide the processor allocation, and to use a flexible programming model that adapts applications to system decisions.
BibTeX:
@inproceedings{Corbalan2001,
  author = {Corbalán, Julita and Martorell, Xavier and Labarta, Jesús},
  title = {Improving Gang Scheduling through Job Performance Analysis and Malleability},
  booktitle = {Proceedings of the 15th International Conference on Supercomputing (ICS)},
  publisher = {ACM},
  year = {2001},
  pages = {303--311},
  url = {papers/Corbalan2001.pdf},
  doi = {papers/Corbalan2001.pdf}
}
Coskun, A.K. and Rosing, T.S. Static and Dynamic Temperature--Aware Scheduling for Multiprocessor SoCs 2008 IEEE Transactions on Very Large Scale Integration Systems (VLSI)
Vol. 16(9), pp. 1127-1140 
article DOI URL 
Abstract: Thermal hot spots and high temperature gradients degrade reliability and performance, and increase cooling costs and leakage power. In this paper, we explore the benefits of temperature--aware task scheduling for multiprocessor system-on-a-chip (MPSoC). We evaluate our techniques using workload characteristics collected from a real system by Sun's Continuous System Telemetry. We first solve the task scheduling problem statically using integer linear programming (ILP). The ILP solution is guaranteed to be optimal for the given assumptions for tasks. We formulate ILPs for minimizing energy, balancing energy, and reducing hot spots, and provide an extensive comparison of their thermal behavior against our technique. Our static solution can reduce the frequency of hot spots by 35%, spatial gradients by 85%, and thermal cycles by 61% in comparison to the ILP for minimizing energy. We then design dynamic scheduling policies at the OS-level with negligible performance overhead. Our adaptive dynamic policy reduces the frequency of high-magnitude thermal cycles and spatial gradients by around 50% and 90%, respectively, in comparison to state-of-the-art schedulers. Reactive thermal management strategies, such as thread migration, can be combined with our scheduling policy to further reduce hot spots, temperature variations, and the associated performance cost.
BibTeX:
@article{Coskun2008,
  author = {Coskun, Ayse Kivilcim and Rosing, Tajana Simunic},
  title = {Static and Dynamic Temperature--Aware Scheduling for Multiprocessor SoCs},
  journal = {IEEE Transactions on Very Large Scale Integration Systems (VLSI)},
  year = {2008},
  volume = {16},
  number = {9},
  pages = {1127--1140},
  url = {papers/Coskun2008.pdf},
  doi = {http://doi.org/10.1109/TVLSI.2008.2000726}
}
Courbin, P. Scheduling Sequential or Parallel Hard Real--Time Pre-emptive Tasks upon Identical Multiprocessor platforms 2013 School: Université Paris--Est  phdthesis URL 
Abstract: In this work, we are interested in the problem of scheduling independent tasks on a hard Real--Time (RT) system composed of multiple processors. A RT system is a system that has time constraints (or timeliness constraints) such that the correctness of these systems depends on the correctness of results it provides, but also on the time instant the results are available. In order to constrain the availability of results, we generally use the concept of "deadline". In a "hard" RT system, the respect of temporal constraints is essential since a missed deadline may cause catastrophic consequences. For example, in the management of train traffic, if a train must use a railroad switch it is important to properly position it before the train arrives or a collision may occur. Thus, the problem of scheduling tasks on a hard RT system consists in nding a way to choose, at each time instant, which tasks should be executed on the processors so that each task succeeds to complete its work before its deadline. We are interested in the scheduling of Sequential Tasks (S-Tasks) (tasks use one processor at a time) and Parallel Tasks
(P--Tasks) (tasks may use multiple processors at a time) in hard RT systems composed of identical multiprocessor platforms (the processors in the platform are strictly identical). In the literature of the state-of-the-art, there are various approaches to schedule these systems.

Regarding S--Tasks scheduling, results have been proposed using the so-called Partitioned Scheduling (P-Scheduling) approach which has the advantage of reducing the problem containing multiple processors to multiple problems containing a single processor. This approach has received much attention, but it poses a problem: it can give poor results for task sets with a high utilization of the processors. For example, it can be shown that in some pathological task configurations, we can only ensure the schedulability of a system which uses less than 50% of the processors capacities. Notice that we compute the task utilization of processor capacity according to the execution time required by the task and its recurrence: if a task needs 2 milliseconds on a processor to complete its execution and it has to be executed again each 4 milliseconds, then this task requires 2/4 x 100 = 50% of the processor capacity. As a consequence of this poor results, the Global Scheduling (G-Scheduling) approach has been proposed and allows, in theory, to fully use the processors capacities. However, this approach poses another problem: it induces many migrations of tasks between processors which can lead to additional costs that are still poorly mastered in the state-of-the-art of RT
scheduling. Thus, a hybrid solution has been proposed, the Semi--Partitioned Scheduling (SP-Scheduling) approach, which aims at minimizing the number of tasks that can migrate between processors.
Regarding P--Tasks scheduling, recent research are very diverse because, in addition to several approaches, there are also several models to represent P-Tasks. The Gang model considers that there are many communications between concurrent threads of a P-Task and therefore requires scheduling them simultaneously. In contrast, the Multi-Thread model assumes that threads are independent. The synchronization between threads is generally defined by successive phases. Each phase is activated when all threads of the previous phase have been completed. This is particularly the case of the Fork-Join model.

In this thesis, we first study S--Tasks scheduling problem. For the P-Scheduling approach, we study different partitioning algorithms proposed in the literature of the state-of-the-art in order to elaborate a generic partitioning algorithm. Especially, we investigate four main placement heuristics (First-Fit, Best-Fit, Next-Fit and Worst-Fit), eight criteria for sorting tasks and seven schedulability tests for Earliest Deadline First (EDF), Deadline Monotonic (DM) and Rate Monotonic (RM) schedulers. It is equivalent to 224 potential P-Scheduling
algorithms. Then, we analyse each of the parameters of this algorithm to extract the best choices according to various objectives. Afterwards, we study the SP--Scheduling approach for which we propose a solution for each of the two sub-categories: with Restricted Migrations (Rest-Migrations) where migrations are only allowed between two successive activations of the task (in other words, between two jobs of the task, thus only task migration
is allowed), and with UnRestricted Migrations (UnRest--Migrations) where migrations are not restricted to job boundaries (job migration is allowed). We provide schedulability tests and an evaluation for EDF scheduler in order to find advantages and disadvantages of each sub-category. In particular, we observe that the approach
with UnRest--Migration gives the best results in terms of number of task sets successfully scheduled. However, we observe a limit on the ability of this approach to split tasks between many processors: if the execution time of the task is too small compared to the time granularity of processor execution, it will be impossible to split the execution time. Thus, the Rest-Migration approach is still interesting, especially as its implementation seems to be easier to achieve on real systems.

Regarding P--Tasks scheduling problem, we propose the Multi-Phase Multi-Thread (MPMT) task model which is a new model for Multi-Thread tasks to facilitate scheduling and analysis. We also provide schedulability tests and a
method for transcribing Fork--Join tasks to our new task model. An exact computation of the Worst Case Response Time (WCRT) of a periodic MPMT task is given as well as a WCRT bound for the sporadic case. Finally, we propose an evaluation to compare Gang and Multi-Thread approaches in order to analyse the advantages and disadvantages. In particular, even if we show that both approaches are incomparable (there are task sets which are schedulable using Gang approach and not by using Multi-Thread approach, and conversely), the Multi-
Thread model allows us to schedule a larger number of task sets and it reduces the WCRT of tasks. Thus, if the tasks are not too complex and do not require too much communication between concurrent threads, it seems interesting to model them with a Multi--Thread approach.

Finally, we have developed a framework called Framework fOr Real--Time Analysis and Simulation (FORTAS) to facilitate evaluations and tests of multiprocessor scheduling algorithms. Its particularity is to provide a programming library to accelerate the development and testing of RT scheduling algorithms. This framework will be proposed as an open source library for the research community.

BibTeX:
@phdthesis{Courbin2013,
  author = {Courbin, Pierre},
  title = {Scheduling Sequential or Parallel Hard Real--Time Pre-emptive Tasks upon Identical Multiprocessor platforms},
  school = {Université Paris--Est},
  year = {2013},
  url = {papers/Courbin2013.pdf}
}
Courbin, P. and George, L. FORTAS : Framework fOr Real-Time Analysis and Simulation 2011 Proceedings of 2nd International Workshop on Analysis Tools and Methodologies for Embedded and Real--Time Systems (WATERS), pp. 21-26  inproceedings URL 
Abstract: Research in real--time scheduling has produced a large number of algorithms with their associated feasibility conditions to respond to the increasing complexity of multiprocessors architectures. However, it is difficult to find tools able to evaluate and compare these algorithms based on simulations or on analytical tests. Our tool named FORTAS offers to facilitate the comparison between different algorithms for uniprocessor and multiprocessors real-time scheduling. Developed in Java with a programming paradigm oriented to modules and abstraction, it gives the user the opportunity to develop their own extensions. Moreover, it proposes to automate the process of comparing different algorithms: generation of sets of tasks, computation of results for each algorithm and generation of graphs for comparison. FORTAS has already been used effectively for various published papers ([1], [2], [3], [4]).
BibTeX:
@inproceedings{Courbin2011,
  author = {Courbin, Pierre and George, Laurent},
  title = {FORTAS : Framework fOr Real-Time Analysis and Simulation},
  booktitle = {Proceedings of 2nd International Workshop on Analysis Tools and Methodologies for Embedded and Real--Time Systems (WATERS)},
  year = {2011},
  pages = {21--26},
  url = {papers/Courbin2011.pdf}
}
Cros, O., Fauberteau, F., George, L. and Li, X. Mixed-criticality over switched Ethernet networks 2014 Proceedings of the 1st Workshop on Mixed Criticality for Industrial Systems (WMCIS)  inproceedings  
Abstract: In this paper, we focus on real--time switched Ethernet networks with mixed-criticality constraints. We are interested in (i) exploiting IEEE 1588 Precision Time Protocol (PTP) to implement criticality propagation techniques in such networks and (ii) analyzing delay of criticality switching. This work presents how to integrate criticality concepts for messages sent on Ethernet networks using PTP protocol. Concerning the delay of criticality switching, we consider FIFO scheduling policy.
BibTeX:
@inproceedings{Cros2014,
  author = {Cros, Olivier and Fauberteau, Frédéric and George, Laurent and Li, Xiaoting},
  title = {Mixed-criticality over switched Ethernet networks},
  booktitle = {Proceedings of the 1st Workshop on Mixed Criticality for Industrial Systems (WMCIS)},
  year = {2014}
}
Cros, O. and George, L. Mixed-criticality management of Networked Real-Time Systems with ARTEMIS Simulator 2015 Proceedings of the 6th International Workshop on Analysis Tools and Methodologies for Embedded and Real-time Systems (WATERS)  inproceedings URL 
Abstract: Nowadays, providing guarantees of performances and reliability in real-time systems implies to have simulation tools in order to test and emulate the systems. The real-time network infrastructures are not an exception to this rule, and needs their own simulators too. Our goal here is to present a new network simulator, ARTEMIS, which is designed to integrate mixed-criticality management in real-time networked systems. Our point here is to show simulation results of ARTEMIS, especially in mixed-criticality context, and to present the main different modules of this software.
BibTeX:
@inproceedings{Cros2015,
  author = {Cros, Olivier and George, Laurent},
  title = {Mixed-criticality management of Networked Real-Time Systems with ARTEMIS Simulator},
  booktitle = {Proceedings of the 6th International Workshop on Analysis Tools and Methodologies for Embedded and Real-time Systems (WATERS)},
  year = {2015},
  url = {papers/Cros2015.pdf}
}
Cros, O., George, L., Fauberteau, F. and Li, X. Simulating real-time and embedded networks scheduling scenarios with ARTEMIS 2014 Proceedings of the 5th International Workshop on Analysis Tools and Methodologies for Embedded and Real-time Systems (WATERS)  inproceedings  
Abstract: Many real--time industrial applications are subject to strong constraints in terms of performance and reliability. These constraints directly increase the cost of the infrastructures needed to deploy these applications. In this work, we focus on the network part of these infrastructures. In order to design and test them, we developed ARTEMIS: Another Real-Time Engine for Message-Issued Simulator. Its aim is to implement all real-time networks like CAN or AFDX, to simulate their behaviors in terms of scheduling and to perform timing analysis. In order to provide genericness, we have built ARTEMIS as a two-parts kernel on which working modules are plugged. In addition to adopting a modular design, it integrates advanced scheduling concepts as mixed-criticality and provides powerful analysis techniques as holistic approach or trajectory approach. Another interesting feature of ARTEMIS is the possibility to interface it with a real industrial network.
BibTeX:
@inproceedings{Cros2014a,
  author = {Cros, Olivier and George, Laurent and Fauberteau, Frédéric and Li, Xiaoting},
  title = {Simulating real-time and embedded networks scheduling scenarios with ARTEMIS},
  booktitle = {Proceedings of the 5th International Workshop on Analysis Tools and Methodologies for Embedded and Real-time Systems (WATERS)},
  year = {2014}
}
Cruz, R.L. A calculus for network delay. I. Network elements in isolation 1991 IEEE Transactions on Information Theory
Vol. 37(1), pp. 114-131 
article DOI URL 
Abstract: A calculus is developed for obtaining bounds on delay and buffering requirements in a communication network operating in a packet switched mode under a fixed routing strategy. The theory developed is different from traditional approaches to analyzing delay because the model used to describe the entry of data into the network is nonprobabilistic. It is supposed that the data stream entered into the network by any given user satisfies burstiness constraints. A data stream is said to satisfy a burstiness constraint if the quantity of data from the stream contained in any interval of time is less than a value that depends on the length of the interval. Several network elements are defined that can be used as building blocks to model a wide variety of communication networks. Each type of network element is analyzed by assuming that the traffic entering it satisfies bursting constraints. Under this assumption, bounds are obtained on delay and buffering requirements for the network element; burstiness constraints satisfied by the traffic that exits the element are derived.
BibTeX:
@article{Cruz1991,
  author = {Cruz, Rene L.},
  title = {A calculus for network delay. I. Network elements in isolation},
  journal = {IEEE Transactions on Information Theory},
  year = {1991},
  volume = {37},
  number = {1},
  pages = {114--131},
  url = {papers/Cruz1991.pdf},
  doi = {http://doi.org/10.1109/18.61109}
}
Cruz, R.L. A calculus for network delay. II. Network analysis 1991 IEEE Transactions on Information Theory
Vol. 37(1), pp. 132-141 
article DOI URL 
Abstract: For pt.I see ibid., vol.37, no.1, p.114--31 (1991). A method to analyze the flow of data in a network consisting of the interconnection of network elements is presented. Assuming the data that enters the network satisfies burstiness constraints, burstiness constraints are derived for traffic flowing between network elements. These derived constraints imply bounds on network delay and buffering requirements. By example, it is shown that the use of regulator elements within the network can reduce maximum network delay. It is also found that such a use of regulator elements can enlarge the throughput region where finite bounds for delay are found. Finally, it is shown how regulator elements connected in series can be used to enforce general burstiness constraints.
BibTeX:
@article{Cruz1991a,
  author = {Cruz, Rene L.},
  title = {A calculus for network delay. II. Network analysis},
  journal = {IEEE Transactions on Information Theory},
  year = {1991},
  volume = {37},
  number = {1},
  pages = {132--141},
  url = {papers/Cruz1991a.pdf},
  doi = {http://doi.org/10.1109/18.61110}
}
Cucinotta, T., Anastasi, G. and Abeni, L. Respecting Temporal Constraints in Virtualised Services 2009
Vol. 2Proceedings of the 33rd IEEE Computer Software and Applications Conference (COMPSAC), pp. 73-78 
inproceedings DOI URL 
Abstract: This paper reports some experiences in providing service guarantees to real-time (RT) applications running in virtual Machine (VM), showing how proper scheduling is a necessary condition for a predictable execution. In particular, resource reservation techniques allow to cope with some of the overhead and unpredictabilities experienced when executing multiple VMs on the same host.
BibTeX:
@inproceedings{Cucinotta2009,
  author = {Cucinotta, Tommaso and Anastasi, Gaetano and Abeni, Luca},
  title = {Respecting Temporal Constraints in Virtualised Services},
  booktitle = {Proceedings of the 33rd IEEE Computer Software and Applications Conference (COMPSAC)},
  year = {2009},
  volume = {2},
  pages = {73--78},
  url = {/papers/Cucinotta2009.pdf},
  doi = {http://doi.org/10.1109/COMPSAC.2009.118}
}
Cucu, L. Ordonnancement non préemptif et condition d'ordonnançabilité pour systèmes embarqués à contraintes temps réel 2004 School: Université Paris Sud -- Paris XI  phdthesis URL 
Abstract: Après un état de l'art sur l'ordonnancement en général et l'ordonnancement temps réel en particulier permetttant de préciser les notions utilisées par la suite et après avoir motivé l'intérêt d'une nouvelle contrainte temps réel de latence, nous proposons un modèle qui formalise les systèmes temps réel avec contraintes de précédences, de périodicités et de latences. Dans ce modèle, les précédences sont définies par un graphe orienté acyclique infiniment répété. Pour le cas monoprocesseur, on étudie trois problèmes d'ordonnancement : celui des systèmes avec contraintes de précédences et de périodicités, celui des systèmes avec contraintes de précédences et de latences et enfin celui des systèmes avec contraintes de précédences, de périodicités et de latences. Pour chaque problème on étudie la cohérence entre les différentes contraintes, on donne des conditions d'ordonnançabilité et on propose un algorithme prouvé optimal dans le sens où s'il y a un ordonnancement, l'algorithme le trouvera. On passe ensuite au cas multiprocesseur où l'architecture est définie par un graphe non--orienté. On étudie trois problèmes d'implantation (distribution et ordonnancement) dans les mêmes cas qu'en monoprocesseur en tenant compte des temps de communications. On prouve que ces trois problèmes sont NP-difficiles et on propose, donc, des heuristiques. Les performances de chaque heuristique sont comparées à celles d'algorithme exacte de type "branch and bound", en utilisant des simulations numériques.
BibTeX:
@phdthesis{Cucu2004,
  author = {Cucu, Liliana},
  title = {Ordonnancement non préemptif et condition d'ordonnançabilité pour systèmes embarqués à contraintes temps réel},
  school = {Université Paris Sud -- Paris XI},
  year = {2004},
  url = {papers/Cucu2004.pdf}
}
Cucu, L. and Goossens, J. Feasibility Intervals for Fixed--Priority Real-Time Scheduling on Uniform Multiprocessors 2006 Proceedings of the 11th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA), pp. 397-405  inproceedings DOI URL 
Abstract: In this paper we study the global scheduling of periodic task systems upon uniform multiprocessor platforms. We first show two very general properties which are wellknown for uniprocessor platforms and which remain for multiprocessor one: (i) under few and not so restrictive assumptions, we show that any feasible schedules of periodic task system are periodic from some point and (ii) for the specific case of synchronous periodic task systems, we show that the schedule repeats from the origin. We then present our main result: any feasible schedules of asynchronous periodic task sets using a fixed--priority scheduler are periodic from a specific point. Moreover, we characterize that point and we provide a feasibility interval for those systems.
BibTeX:
@inproceedings{Cucu2006,
  author = {Cucu, Liliana and Goossens, Joël},
  title = {Feasibility Intervals for Fixed--Priority Real-Time Scheduling on Uniform Multiprocessors},
  booktitle = {Proceedings of the 11th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA)},
  year = {2006},
  pages = {397--405},
  url = {papers/Cucu2006.pdf},
  doi = {http://doi.org/10.1109/ETFA.2006.355388}
}
Dafang, W., Jiuyang, Z., Guifan, Z., Bo, H. and Shiqiang, L. Survey of the AUTOSAR Complex Drivers in the Field of Automotive Electronics 2010 Proceedings of the International Conference on Intelligent Computation Technology and Automation (ICICTA), pp. 662-664  inproceedings DOI URL 
Abstract: The Complex Device Driver is a loosely coupled container, where specific software implementations can be placed. The only requirement to the software parts is that the interface to the AUTOSAR system has to be implemented according to the AUTOSAR port and interface specifications. The purpose of the Complex Device Drivers is to fulfill the special functional and timing requirements for handling complex sensors and actuators. It is used to handle the tasks related to the strict timing. The Complex Device Drivers are to some extend intended as a migration mechanism. If interfaces for extensions are defined according to the AUTOSAR standards new extensions can be implemented according to the AUTOSAR standards, which will not force the OEM nor the supplier to reengineer all existing applications.
BibTeX:
@inproceedings{Dafang2010,
  author = {Dafang, Wang and Jiuyang, Zheng and Guifan, Zhao and Bo, Huang and Shiqiang, Liu},
  title = {Survey of the AUTOSAR Complex Drivers in the Field of Automotive Electronics},
  booktitle = {Proceedings of the International Conference on Intelligent Computation Technology and Automation (ICICTA)},
  publisher = {IEEE},
  year = {2010},
  pages = {662--664},
  url = {10.1109/ICICTA.2010.534},
  doi = {papers/Dafang2010.pdf}
}
Davari, S. and Dhall, S.K. An On Line Algorithm for Real--Time Tasks Allocation 1986 Proceedings of the 11th IEEE Real--Time Systems Symposium (RTSS), pp. 194-200  inproceedings  
BibTeX:
@inproceedings{Davari1986,
  author = {Davari, Sadegh and Dhall, Sudarshan Kumar},
  title = {An On Line Algorithm for Real--Time Tasks Allocation},
  booktitle = {Proceedings of the 11th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1986},
  pages = {194--200}
}
David, R., Chillet, D., Pillement, S. and Sentieys, O. DART: A Dynamically Reconfigurable Architecture Dealing with Future Mobile Telecommunications Constraints 2002 Proceedings of the 16th International Parallel and Distributed Processing Symposium (IPDPS), pp. 156  inproceedings DOI URL 
Abstract: In addition to the high performance requirements inherent to multimedia processings or to W--CDMA, future generation mobile telecommunications brings new constraints to the semiconductor design world. In fact, to support these processings, a system will have to be very flexible, in order to support the various algorithms allowed by the norm and the addition of new services, while keeping an energy consumption level compatible with the portability notion of this system. In order to associate high performances and low energy consumption in a flexible system, we developed a dynamically reconfigurable architecture called DART. The aim of this paper is to present this architecture and to estimate its level of performance and its adequacy with future generation mobile telecommunication systems.
BibTeX:
@inproceedings{David2002a,
  author = {David, Raphël and Chillet, Daniel and Pillement, Sébastien and Sentieys, Olivier},
  title = {DART: A Dynamically Reconfigurable Architecture Dealing with Future Mobile Telecommunications Constraints},
  booktitle = {Proceedings of the 16th International Parallel and Distributed Processing Symposium (IPDPS)},
  publisher = {IEEE Computer Society},
  year = {2002},
  pages = {156},
  url = {papers/David2002a.pdf},
  doi = {http://doi.org/10.1109/IPDPS.2002.1016554}
}
David, V. and Delcoigne, J. Security Method Making Deterministic Real Time Execution of Multitask Applications of Control and Command Type with Error Confinement 2002 (W0 02/39277 A1)  patent URL 
Abstract: The method is implemented with a management system of the time--triggered architecture type in association with a processor of a central processor unit that possesses a privileged execution mode to which access is protected by an instruction of the "call to system layer" type. The only system layer call that is authorized from an application task under consideration to the system layer consists in reporting a change of node in the control graph of the task in question. When the system layer has verified that the call is legal relative to the execution paths of the control graph as described in the constant tables of the application, all of the operations to be performed on the node in question by the system layer are predetermined by the constant tables of the application associated with the system layer. Prior to real-time execution, pre-ordering of the lists of tasks of an application under consideration is performed in a micro-kernel, which subsequently ensures, when called by the system layer during real-time execution, that task lists are updated in ordered manner depending on the new time characteristics of the tasks, specifically their earliest start times d(i) and their latest finish times f(i) as calculated by the system layer.
BibTeX:
@patent{David2002,
  author = {David, Vincent and Delcoigne, Jean},
  title = {Security Method Making Deterministic Real Time Execution of Multitask Applications of Control and Command Type with Error Confinement},
  year = {2002},
  number = {W0 02/39277 A1},
  url = {papers/David2002.pdf}
}
David, V., Delcoigne, J., Leret, E., Ourghanlian, A., Hilsenkopf, P. and Paris, P. Safety Properties Ensured by the OASIS Model for Safety Critical Real--Time Systems 1998
Vol. 1516Proceedings of the 17th International Conference on Computer Safety, Reliability and Security (SAFECOMP), pp. 45-59 
inproceedings DOI URL 
Abstract: The main focus of this paper is the problem of ensuring safety properties such as timeliness in safety critical systems. We introduce the OASIS model and its associated techniques to model both real--time tasks and to ensure determinism and dependability concerns when tasks are executed in parallel. By this approach we will show some formal aspects of our real-time task model and also how this result is used to ensure that the timeliness property and the sizing can be achieved on a safety critical real-time study case.
BibTeX:
@inproceedings{David1998,
  author = {David, Vincent and Delcoigne, Jean and Leret, Evelyne and Ourghanlian, Alain and Hilsenkopf, Philippe and Paris, Philippe},
  title = {Safety Properties Ensured by the OASIS Model for Safety Critical Real--Time Systems},
  booktitle = {Proceedings of the 17th International Conference on Computer Safety, Reliability and Security (SAFECOMP)},
  publisher = {Springer},
  year = {1998},
  volume = {1516},
  pages = {45--59},
  url = {papers/David1998.pdf},
  doi = {http://doi.org/10.1007/3--540-49646-7_4}
}
Davis, R.I. On Exploiting Spare Capacity in Hard Real--Time Systems 1995 School: University of York  phdthesis URL 
Abstract: Complex real--time systems such as those envisaged for future autonomous vehicle control, robotics and advanced avionics applications, need to exhibit dynamic and adaptive behaviour in order to function in unpredictable environments. These systems need to be resilient to software / hardware failures and imbibed with the property of graceful degradation under overload. Cost, space and weight constraints also dictate that they must make the most effective use of limited processing / communications resources. To realise such complex systems, two potentially conflicting objectives need to be met: first, safety critical and mission critical services must be guaranteed to provide results of a minimum acceptable quality and reliability by their deadlines. Second, the utility of the system, as determined by the frequency, timeliness, precision and confidence level of the results produced, must be maximised. The research comprising this thesis, focuses on the development of analysis and mechanisms which enable this second objective to be met. System utility can be enhanced by the timely execution of optional components which refine or improve upon the results of their mandatory counterparts. To achieve this, a three tier strategy is proposed. Initially, algorithms are developed which identify spare capacity at run-time, enabling optional components with soft deadlines to be scheduled responsively. Second, a family of acceptance tests are introduced, which facilitate the on-line guarantee of optional components with firm deadlines. An optimal priority assignment policy is derived for such components. Third, an efficient, adaptive admission policy is developed which arbitrates between competing optional components on the basis of their value-densities, enabling system utility to be maximised. The effectiveness of these techniques is examined in terms of their coverage, simplicity, performance and overheads, via simulation studies and via a proof of concept implementation within a hard real-time kernel.
BibTeX:
@phdthesis{Davis1995,
  author = {Davis, Robert Ian},
  title = {On Exploiting Spare Capacity in Hard Real--Time Systems},
  school = {University of York},
  year = {1995},
  url = {papers/Davis1995.pdf}
}
Davis, R.I. and Burns, A. Mixed Criticality on Controller Area Network 2013 Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS), pp. 125-134  inproceedings DOI URL 
Abstract: An increasingly important trend in the design of real--time and embedded systems is the integration of components with different levels of criticality onto a common hardware platform. Where the platform incorporates a communication media it is necessary for that media to be able to safely and efficiently transfer messages of different criticality levels. In this paper we consider the Controller Area Network (CAN), and define mixed criticality protocols that could form the basis of a Trusted Network Component for CAN. Sufficient response-time analysis is derived for these protocols and an optimal priority assignment scheme is provided. Evaluations illustrate the benefits of the schemes.
BibTeX:
@inproceedings{Davis2013,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {Mixed Criticality on Controller Area Network},
  booktitle = {Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2013},
  pages = {125--134},
  url = {papers/Davis2013.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2013.23}
}
Davis, R.I. and Burns, A. A Survey of Hard Real--Time Scheduling for Multiprocessor Systems 2011 ACM Computing Surveys
Vol. 43(4), pp. 44 
article DOI URL 
Abstract: This survey covers hard real--time scheduling algorithms and schedulability analysis techniques for homogeneous multiprocessor systems. It reviews the key results in this field from its origins in the late 1960’s to the latest research published in late 2009. The survey outlines fundamental results about multiprocessor real-time scheduling that hold independent of the scheduling algorithms employed. It provides a taxonomy of the different scheduling methods, and considers the various performance metrics that can be used for comparison purposes. A detailed review is provided covering partitioned, global, and hybrid scheduling algorithms, approaches to resource sharing, and the latest results from empirical investigations. The survey identifies open issues, key research challenges and likely productive research directions.
BibTeX:
@article{Davis2011a,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {A Survey of Hard Real--Time Scheduling for Multiprocessor Systems},
  journal = {ACM Computing Surveys},
  year = {2011},
  volume = {43},
  number = {4},
  pages = {44},
  url = {papers/Davis2011a.pdf},
  doi = {http://doi.org/10.1145/1978802.1978814}
}
Davis, R.I. and Burns, A. FPZL Schedulability Analysis 2011 Proceedings of the 17th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS), pp. 245-256  inproceedings DOI URL 
Abstract: This paper presents the Fixed Priority until Zero Laxity (FPZL) scheduling algorithm for multiprocessor realtime systems. FPZL is similar to global fixed priority preemptive scheduling, however, whenever a task reaches a state of zero laxity it is given the highest priority. FPZL is a minimally dynamic algorithm, in that the priority of a job can change at most once during its execution, bounding the number of pre--emptions. Polynomial time and pseudopolynomial time sufficient schedulability tests are derived for FPZL. These tests are then improved by computing upper bounds on the amount of execution that each task can perform in the zero laxity state. An empirical evaluation shows that FPZL is highly effective, with a significantly larger number of task sets deemed schedulable by the tests derived in this paper, than by state-of-the-art schedulability tests for Earliest Deadline until Zero Laxity (EDZL) scheduling.
BibTeX:
@inproceedings{Davis2011,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {FPZL Schedulability Analysis},
  booktitle = {Proceedings of the 17th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS)},
  publisher = {IEEE Computer Society},
  year = {2011},
  pages = {245--256},
  url = {papers/Davis2011.pdf},
  doi = {http://doi.org/10.1109/RTAS.2011.31}
}
Davis, R.I. and Burns, A. A Survey of Hard Real--Time Scheduling for Multiprocessor Systems 2010 ACM Computing Surveys (CSUR)  article URL 
Abstract: This survey covers hard real--time scheduling algorithms and schedulability analysis techniques for homogeneous multiprocessor systems. It reviews the key results in this field from its origins in the late 1960’s to the latest research published in late 2009. The survey outlines fundamental results about multiprocessor real- time scheduling that hold independent of the scheduling algorithms employed. It provides a taxonomy of the different scheduling methods, and considers the various performance metrics that can be used for comparison purposes. A detailed review is provided covering partitioned, global, and hybrid scheduling algorithms, approaches to resource sharing, and the latest results from empirical investigations. The survey identifies open issues, key research challenges and likely productive research directions.
BibTeX:
@article{Davis2010a,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {A Survey of Hard Real--Time Scheduling for Multiprocessor Systems},
  journal = {ACM Computing Surveys (CSUR)},
  year = {2010},
  url = {papers/Davis2010a.pdf}
}
Davis, R.I. and Burns, A. FPZL Schedulability Analysis 2010 (YCS-2010-452)School: University of York  techreport URL 
Abstract: This paper presents the FPZL scheduling algorithm for multiprocessor real--time systems. FPZL is similar to global fixed priority pre-emptive scheduling; however, whenever a task reaches a state of zero laxity it is given the highest priority. FPZL is a minimally dynamic algorithm, in that the priority of a job can change at most once during its execution. Polynomial time and pseudo-polynomial time sufficient schedulability tests are derived for FPZL. These tests are then improved by computing upper bounds on the amount of execution that each task can perform in the zero laxity state. An empirical evaluation shows that FPZL is highly effective, with a significantly larger number of tasksets deemed schedulable by the tests derived in this paper, than by state-of-the-art schedulability tests for EDZL scheduling.
BibTeX:
@techreport{Davis2010b,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {FPZL Schedulability Analysis},
  school = {University of York},
  year = {2010},
  number = {YCS--2010-452},
  url = {papers/Davis2010b.pdf}
}
Davis, R.I. and Burns, A. Improved priority assignment for global fixed priority pre--emptive scheduling in multiprocessor real-time systems 2010 Real-Time Systems
Vol. 47(1), pp. 1-40 
article DOI URL 
Abstract: This paper is an extended version of a paper that appeared in the proceedings of the IEEE Real--Time Systems Symposium 2009. This paper has been updated with respect to advances made in schedulability analysis, and contains a number of significant additional results. The paper addresses the problem of priority assignment in multiprocessor real-time systems using global fixed task-priority pre-emptive scheduling. We prove that Audsley’s Optimal Priority Assignment (OPA) algorithm, originally devised for uniprocessor scheduling, is applicable to the multiprocessor case, provided that three conditions hold with respect to the schedulability tests used. Our empirical investigations show that the combination of optimal priority assignment policy and a simple compatible schedulability test is highly effective in terms of the number of tasksets deemed to be schedulable. We also examine the performance of heuristic priority assignment policies such as Deadline Monotonic, and an extension of the TkC priority assignment policy called DkC that can be used with any schedulability test. Here we find that Deadline Monotonic priority assignment has relatively poor performance in the multiprocessor case, while DkC priority assignment is highly effective.
BibTeX:
@article{Davis2010,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {Improved priority assignment for global fixed priority pre--emptive scheduling in multiprocessor real-time systems},
  journal = {Real-Time Systems},
  year = {2010},
  volume = {47},
  number = {1},
  pages = {1--40},
  url = {papers/Davis2010.pdf},
  doi = {http://doi.org/10.1007/s11241--010-9106-5}
}
Davis, R.I. and Burns, A. A Survey of Hard Real--Time Scheduling Algorithms and Schedulability Analysis Techniques for Multiprocessor Systems 2009 (YCS-2009-443)School: University of York, Department of Computer Science  techreport URL 
Abstract: This survey covers hard real--time scheduling algorithms and schedulability analysis techniques for homogeneous multiprocessor systems. It reviews the key results in this field from its origins in the late 1960’s to the latest research published in late 2009. The survey outlines fundamental results about multiprocessor realtime scheduling that hold independent of the scheduling algorithms employed. It provides a taxonomy of the different scheduling methods, and considers the various performance metrics that can be used for comparison purposes. A detailed review is provided covering partitioned, global, and hybrid scheduling algorithms, approaches to resource sharing, and the latest results from empirical investigations. The survey identifies open issues, key research challenges and likely productive research directions.
BibTeX:
@techreport{Davis2009,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {A Survey of Hard Real--Time Scheduling Algorithms and Schedulability Analysis Techniques for Multiprocessor Systems},
  school = {University of York, Department of Computer Science},
  year = {2009},
  number = {YCS--2009-443},
  url = {papers/Davis2009.pdf}
}
Davis, R.I. and Burns, A. Priority Assignment for Global Fixed Priority Pre--Emptive Scheduling in Multiprocessor Real-Time Systems 2009 Proceedings of the 30th IEEE Real-Time Systems Symposium (RTSS), pp. 398-409  inproceedings DOI URL 
Abstract: This paper addresses the problem of priority assignment in multiprocessor real--time systems using global fixed task-priority pre-emptive scheduling. In this paper, we prove that Audsley's Optimal Priority Assignment (OPA) algorithm, originally devised for uniprocessor scheduling, is applicable to the multiprocessor case, provided that three conditions hold with respect to the schedulability tests used. Our empirical investigations show that the combination of optimal priority assignment policy and a simple compatible schedulability test is highly effective, in terms of the number of tasksets deemed to be schedulable. We also examine the performance of heuristic priority assignment policies such as Deadline Monotonic, and an extension of the TkC priority assignment policy called DkC that can be used with any schedulability test. Here we find that Deadline Monotonic priority assignment has relatively poor performance in the multiprocessor case, while DkC priority assignment is highly effective.
BibTeX:
@inproceedings{Davis2009a,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {Priority Assignment for Global Fixed Priority Pre--Emptive Scheduling in Multiprocessor Real-Time Systems},
  booktitle = {Proceedings of the 30th IEEE Real-Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {398--409},
  url = {papers/Davis2009a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2009.31}
}
Davis, R.I. and Burns, A. Robust Priority Assignment for Fixed Priority Real--Time Systems 2007 Proceedings of the 28th IEEE Real-Time Systems Symposium (RTSS), pp. 3-14  inproceedings URL 
Abstract: This paper focuses on priority assignment for realtime systems using fixed priority scheduling. It introduces and defines the concept of a “robust” priority ordering: the most appropriate priority ordering to use in a system subject to variable amounts of additional interference from sources such as interrupts, operating system overheads, exception handling, cycle stealing, and task execution time overruns. The paper describes a Robust Priority Assignment algorithm that can find the robust priority ordering for a wide range of fixed priority system models and additional interference functions. Proofs are given for a number of interesting theorems about robust priority assignment, and the circumstances under which a “Deadline minus Jitter” monotonic partial ordering forms part of the robust ordering. The paper shows that “Deadline minus Jitter” monotonic priority ordering is the robust priority ordering for a specific class of system, and that this property holds essentially independent of the additional interference function.
BibTeX:
@inproceedings{Davis2007,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {Robust Priority Assignment for Fixed Priority Real--Time Systems},
  booktitle = {Proceedings of the 28th IEEE Real-Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {3--14},
  url = {papers/Davis2007.pdf}
}
Davis, R.I. and Burns, A. Hierarchical fixed priority pre-emptive scheduling 2005 Proceedings of the 26th IEEE Real-Time Systems Symposium (RTSS), pp. 389-398  inproceedings DOI URL 
Abstract: This paper focuses on the hierarchical scheduling of systems where a number of separate applications reside on a single processor. It addresses the particular case where fixed priority pre-emptive scheduling is used at both global and local levels, with a server associated with each application. Using response time analysis, an exact schedulability test is derived for application tasks. This test improves on previously published work. The analysis is extended to the case of harmonic tasks that can be bound to the release of their server. These tasks exhibit improved schedulability indicating that it is advantageous to choose server periods that enable some tasks to be bound to the release of their server. The use of periodic, sporadic and deferrable servers is considered with the conclusion that the simple periodic server dominates both sporadic and deferrable servers when the metric is application task schedulability.
BibTeX:
@inproceedings{Davis2005,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {Hierarchical fixed priority pre-emptive scheduling},
  booktitle = {Proceedings of the 26th IEEE Real-Time Systems Symposium (RTSS)},
  year = {2005},
  pages = {389--398},
  url = {/papers/Davis2005.pdf},
  doi = {http://doi.org/10.1109/RTSS.2005.25}
}
Davis, R.I. and Burns, A. Optimal priority assignment for aperiodic tasks with firm deadlines in fixed priority pre--emptive systems 1995 Information Processing Letters
Vol. 53(5), pp. 249 - 254 
article DOI URL 
Abstract: An optimal priority assignment policy is presented for independent aperiodic tasks with arbitrary ready times and firm deadlines, scheduled on a uniprocessor along with a set of hard periodic/sporadic tasks. The latter tasks are assumed to have been assigned unique fixed priorities according to some arbitrary policy and guaranteed, via off--line feasibility analysis, to meet their deadlines. In contrast, priority assignment and acceptance testing of aperiodic tasks must be carried out on-line. The priority assignment policy introduced is shown to be optimal both in terms of maximising the computation time which can be made available before the aperiodic deadline and with respect to guaranteeing subsequent aperiodic arrivals.
BibTeX:
@article{Davis1995a,
  author = {Davis, Robert Ian and Burns, Alan},
  title = {Optimal priority assignment for aperiodic tasks with firm deadlines in fixed priority pre--emptive systems},
  journal = {Information Processing Letters},
  year = {1995},
  volume = {53},
  number = {5},
  pages = {249 -- 254},
  url = {papers/Davis1995a.pdf},
  doi = {http://doi.org/10.1016/0020--0190(94)00200-I}
}
Davis, R.I., Burns, A., Baruah, S.K., Rothvoß, T., George, L. and Gettings, O. Exact comparison of fixed priority and EDF scheduling based on speedup factors for both pre--emptive and non-pre-emptive paradigms 2015 Real-Time Systems
Vol. 51(5), pp. 566-601 
article DOI URL 
Abstract: This paper investigates the relative effectiveness of fixed priority (FP) scheduling in a uniprocessor system compared to earliest deadline first (EDF) scheduling. The quantitative metric used in this comparison is the processor speedup factor, defined as the factor by which processor speed needs to increase to ensure that any task set that is schedulable according to EDF can be scheduled using fixed priorities. In the pre--emptive case, exact speedup factors are known for sporadic task sets with implicit or constrained deadlines. In this paper, we derive exact speedup factors for both pre-emptive and non-pre-emptive fixed priority scheduling of arbitrary deadline sporadic task sets. We also show that the exact speedup factor for the pre-emptive case holds when tasks share resources according to the stack resource policy/deadline floor protocol.
BibTeX:
@article{Davis2015,
  author = {Davis, Robert Ian and Burns, Alan and Baruah, Sanjoy K. and Rothvoß, Thomas and George, Laurent and Gettings, Olivier},
  title = {Exact comparison of fixed priority and EDF scheduling based on speedup factors for both pre--emptive and non-pre-emptive paradigms},
  journal = {Real-Time Systems},
  year = {2015},
  volume = {51},
  number = {5},
  pages = {566--601},
  url = {papers/Davis2015.pdf},
  doi = {http://doi.org/10.1007/s11241--015-9233-0}
}
Davis, R.I., Burns, A., Pollex, V. and Slomka, F. On Priority Assignment for Controller Area Network when some Message Identifiers are Fixed 2015 Proceedings of the 23rd International Conference on Real-Time Networks and Systems (RTNS), pp. 279-288  inproceedings DOI URL 
Abstract: Controller Area Network (CAN) is widely used in automotive applications. With CAN, the network utilisation that may be obtained while ensuring that all messages meet their deadlines is strongly dependent on the policy used for priority (message identifier) assignment. This paper addresses the problem of priority assignment when some message identifiers are fixed. There are two variants of this problem: P1 where the gaps between fixed identifiers are large enough to accommodate the freely assignable messages and P2 when the gaps are too small. For problem P1, we provide algorithms that give optimal and robust priority orderings based on an adaptation of existing techniques. Problem P2 is more difficult to solve. We show via a counter example that the algorithms derived for P1 and others recently published can fail to find a schedulable priority ordering when the gaps are small, even though one exists. We derive an optimal and robust solution to this problem with respect to a simple form of schedulability analysis which assumes the same upper bound on the length of all messages.
BibTeX:
@inproceedings{Davis2015a,
  author = {Davis, Robert Ian and Burns, Alan and Pollex, Victor and Slomka, Frank},
  title = {On Priority Assignment for Controller Area Network when some Message Identifiers are Fixed},
  booktitle = {Proceedings of the 23rd International Conference on Real-Time Networks and Systems (RTNS)},
  publisher = {ACM Press},
  year = {2015},
  pages = {279--288},
  url = {papers/Davis2015a.pdf},
  doi = {http://doi.org/10.1145/2834848.2834866}
}
Davis, R.I., Burns, A., Reinder, J.B. and Lukkien, J.J. Controller Area Network (CAN) Schedulability Analysis: Refuted, Revisited and Revised 2007 Real-Time Systems
Vol. 35(3), pp. 239-272 
article DOI URL 
Abstract: Controller Area Network (CAN) is used extensively in automotive applications, with in excess of 400 million CAN enabled microcontrollers manufactured each year. In 1994 schedulability analysis was developed for CAN, showing how worst--case response times of CAN messages could be calculated and hence guarantees provided that message response times would not exceed their deadlines. This seminal research has been cited in over 200 subsequent papers and transferred to industry in the form of commercial CAN schedulability analysis tools. These tools have been used by a large number of major automotive manufacturers in the design of in-vehicle networks for a wide range of cars, millions of which have been manufactured during the last decade.

This paper shows that the original schedulability analysis given for CAN messages is flawed. It may provide guarantees for messages that will in fact miss their deadlines in the worst--case. This paper provides revised analysis resolving the problems with the original approach. Further, it highlights that the priority assignment policy, previously claimed to be optimal for CAN, is not in fact optimal and cites a method of obtaining an optimal priority ordering that is applicable to CAN. The paper discusses the possible impact on commercial CAN systems designed and developed using flawed schedulability analysis and makes recommendations for the revision of CAN schedulability analysis tools.

BibTeX:
@article{Davis2007a,
  author = {Davis, Robert Ian and Burns, Alan and Reinder, J. Bril and Lukkien, Johan J.},
  title = {Controller Area Network (CAN) Schedulability Analysis: Refuted, Revisited and Revised},
  journal = {Real-Time Systems},
  year = {2007},
  volume = {35},
  number = {3},
  pages = {239--272},
  url = {papers/Davis2007a.pdf},
  doi = {http://doi.org/10.1007/s11241--007-9012-7}
}
Davis, R.I., Burs, A., Pollex, V. and Slomka, F. On Priority Assignment for Controller Area Network when some Message Identifiers are Fixed 2015 (YCS-2015-498), pp. 12School: Dept. of Computer Science, University of York  techreport URL 
BibTeX:
@techreport{Davis2015b,
  author = {Davis, Robert Ian and Burs, Alan and Pollex, Victor and Slomka, Frank},
  title = {On Priority Assignment for Controller Area Network when some Message Identifiers are Fixed},
  school = {Dept. of Computer Science, University of York},
  year = {2015},
  number = {YCS-2015-498},
  pages = {12},
  url = {papers/Davis2015b.pdf}
}
Davis, R.I., Cucu-Grosjean, L., Bertogna, M. and Burns, A. A review of priority assignment in real-time systems 2016 Journal of Systems Architecture (JSA)
Vol. 65, pp. 64-82 
article DOI URL 
Abstract: It is over 40 years since the first seminal work on priority assignment for real-time systems using fixed priority scheduling. Since then, huge progress has been made in the field of real-time scheduling with more complex models and schedulability analysis techniques developed to better represent and analyse real systems. This tutorial style review provides an in-depth assessment of priority assignment techniques for hard real-time systems scheduled using fixed priorities. It examines the role and importance of priority in fixed priority scheduling in all of its guises, including: pre-emptive and non-pre-emptive scheduling; covering single- and multi-processor systems, and networks. A categorisation of optimal priority assignment techniques is given, along with the conditions on their applicability. We examine the extension of these techniques via sensitivity analysis to form robust priority assignment policies that can be used even when there is only partial information available about the system. The review covers priority assignment in a wide variety of settings including: mixed-criticality systems, systems with deferred pre-emption, and probabilistic real-time systems with worst-case execution times described by random variables. It concludes with a discussion of open problems in the area of priority assignment.
BibTeX:
@article{Davis2016,
  author = {Davis, Robert Ian and Cucu-Grosjean, Liliana and Bertogna, Marko and Burns, Alan},
  title = {A review of priority assignment in real-time systems},
  journal = {Journal of Systems Architecture (JSA)},
  year = {2016},
  volume = {65},
  pages = {64--82},
  url = {papers/Davis2016.pdf},
  doi = {http://doi.org/10.1016/j.sysarc.2016.04.002}
}
Davis, R.I. and Navet, N. Traffic Shaping to Reduce Jitter in Controller Area Network (CAN) 2012 ACM SIGBED Review -- Special Issue on the 24th Euromicro Conference on Real-Time Systems
Vol. 9(4), pp. 37-40 
article DOI URL 
Abstract: When a message is transferred from one CAN bus to another via a gateway, variability in the response time of the message on the source network typically translates into queuing jitter on the destination network. This jitter inheritance accumulates across each gateway and can significantly impact the schedulability of lower priority messages. In this paper, we show that the real--time performance of the network can be enhanced by a simple method of traffic shaping that eliminates this inherited queuing jitter. This method does not require access to global time, nor does it require precise time-stamping of when messages are received at the gateway or blocking read calls. It can also be extended to account for clock drifts between networks.
BibTeX:
@article{Davis2012,
  author = {Davis, Robert Ian and Navet, Nicolas},
  title = {Traffic Shaping to Reduce Jitter in Controller Area Network (CAN)},
  journal = {ACM SIGBED Review -- Special Issue on the 24th Euromicro Conference on Real-Time Systems},
  year = {2012},
  volume = {9},
  number = {4},
  pages = {37--40},
  url = {papers/Davis2012.pdf},
  doi = {http://doi.org/10.1145/2452537.2452544}
}
Davis, R.I., Tindell, K.W. and Burns, A. Scheduling Slack Time in Fixed Priority Pre--emptive Systems 1993 Proceedings of the 14th IEEE Real--Time Systems Symposium (RTSS), pp. 222-231  inproceedings URL 
Abstract: This paper addresses the problem of jointly scheduling tasks with both hard and soft time constraints. We present a new analysis which builds upon previous research into slack stealing algorithms. Our analysis determines the maximum processing time which may be stolen from hard deadline periodic or sporadic tasks, without jeopardising their timing constraints. It extendr to tasks with characteristics such as synchronisation, release jitter and stochastic execution times, as well as forming the basis for a family of optimal and approximate slack stealing algorithms.
BibTeX:
@inproceedings{Davis1993,
  author = {Davis, Robert Ian and Tindell, Ken W. and Burns, Alan},
  title = {Scheduling Slack Time in Fixed Priority Pre--emptive Systems},
  booktitle = {Proceedings of the 14th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1993},
  pages = {222--231},
  url = {papers/Davis1993.pdf}
}
Davis, R.I., Zabos, A. and Burns, A. Efficient Exact Schedulability Tests for Fixed Priority Real--Time Systems 2008 IEEE Transactions on Computers
Vol. 57(9), pp. 1261-1276 
article URL 
Abstract: Efficient exact schedulability tests are required both for on--line admission of applications to dynamic systems and as an integral part of design tools for complex distributed real-time systems. This paper addresses performance issues with exact Response Time Analysis (RTA) for fixed priority pre-emptive systems. Initial values are introduced that improve the efficiency of the standard RTA algorithm (i) when exact response times are required, and (ii) when only exact schedulability need be determined. The paper also explores modifications to the standard RTA algorithm, including; the use of a response time upper bound to determine when exact analysis is needed, incremental computation aimed at faster convergence, and checking tasks in reverse priority order to identify unschedulable tasksets early. The various initial values and algorithm implementations are compared by means of experiments on a PC recording the number of iterations required, and execution time measurements on a real-time embedded microprocessor. Recommendations are provided for engineers tasked with the problem of implementing exact schedulability tests, as part of on-line acceptance tests and spare capacity allocation algorithms, or as part of off-line system design tools.
BibTeX:
@article{Davis2008,
  author = {Davis, Robert Ian and Zabos, Attila and Burns, Alan},
  title = {Efficient Exact Schedulability Tests for Fixed Priority Real--Time Systems},
  journal = {IEEE Transactions on Computers},
  year = {2008},
  volume = {57},
  number = {9},
  pages = {1261--1276},
  url = {papers/Davis2008.pdf}
}
Delchini, H. Conception, développement et évaluation d'un langage de programmation adapté aux applications industrielles : llC 1995 School: Université Paris--Diderot - Paris VII  phdthesis URL 
Abstract: Le développement d'applications informatiques passe souvent par l'utilisation de langages évolués pour la programmation et de systèmes d'exploitation pour la gestion de l'exécution. Une famille de langages de programmation (les LPC pour "langages à parallélisme Compilé") peuvent procurer les même fonctionnalités et avantages qu'un langage de programmation couplé à un système d'exploitation multi--tâches. Notre intention est de montrer que les LPC ont certains attraits supplémentaires surtout dans le domaine d'application qu'est l'informatique industrielle. Pour mettre ceci en évidence, nous avons développé plusieurs versions d'une même application en utilisant d'une part un LPC et, d'autre part, un langage évolué classique avec un système d'exploitation. Ensuite, nous avons fait une comparaison chiffrée des différentes versions.
BibTeX:
@phdthesis{Delchini1995,
  author = {Delchini, Hugo},
  title = {Conception, développement et évaluation d'un langage de programmation adapté aux applications industrielles : llC},
  school = {Université Paris--Diderot - Paris VII},
  year = {1995},
  url = {http://tel.archives--ouvertes.fr/tel-00681055}
}
Deng, Z. and Liu, J.W.-S. Scheduling real-time applications in an open environment 1997 Proceeding of the 18th IEEE Real-Time Systems Symposium (RTSS), pp. 308-319  inproceedings DOI URL 
Abstract: This paper extends the two-level hierarchical scheme in (Deng et al., 1997) for scheduling independently developed real-time applications with non-real-time applications in an open environment. The environment allows the schedulability of each real-time application to be validated independently of other applications in the system. The extended scheme removes the following two restrictions of the scheme: real-time applications that are scheduled preemptively must consist solely of periodic tasks; and applications must not share global resources (i.e., resources used by more than one application). Consequently, the extended scheme can accommodate a much broader spectrum of real-time applications.
BibTeX:
@inproceedings{Deng1997,
  author = {Deng, Z. and Liu, Jane W.-S.},
  title = {Scheduling real-time applications in an open environment},
  booktitle = {Proceeding of the 18th IEEE Real-Time Systems Symposium (RTSS)},
  year = {1997},
  pages = {308--319},
  url = {/papers/Deng1997.pdf},
  doi = {http://doi.org/10.1109/REAL.1997.641292}
}
Dertouzos, M.L. Control robotics: The procedural control of physical processes 1974 Information ProcessingProceedings of IFIP Congress 74, pp. 807-813  inproceedings  
BibTeX:
@inproceedings{Dertouzos1974,
  author = {Dertouzos, Michael Leonidas},
  title = {Control robotics: The procedural control of physical processes},
  booktitle = {Proceedings of IFIP Congress 74},
  journal = {Information Processing},
  publisher = {North--Holland, American Elsevier},
  year = {1974},
  pages = {807--813}
}
Dertouzos, M.L. and Mok, A.K.-L. Multiprocessor On--Line Scheduling of Hard-Real-Time Tasks 1989 IEEE Transactions on Software Engineering
Vol. 15(12), pp. 1497-1506 
article DOI URL 
Abstract: The problems of hard--real-time task scheduling in a multiprocessor environment are discussed in terms of a scheduling game representation of the problem. It is shown that optimal scheduling without a priori knowledge is impossible in the multiprocessor case even if there is no restriction on preemption owing to precedence or mutual exclusion constraints. Sufficient conditions that permit a set of tasks to be optimally scheduled at run time are derived.
BibTeX:
@article{Dertouzos1989,
  author = {Dertouzos, Michael Leonidas and Mok, Aloysius Ka--Lau},
  title = {Multiprocessor On--Line Scheduling of Hard-Real-Time Tasks},
  journal = {IEEE Transactions on Software Engineering},
  year = {1989},
  volume = {15},
  number = {12},
  pages = {1497--1506},
  url = {papers/Dertouzos1989.pdf},
  doi = {http://doi.org/10.1109/32.58762}
}
Devi, U.C. Soft Real--Time Scheduling on Multiprocessors 2006 School: University of North Carolina  phdthesis URL 
Abstract: The design of real--time systems is being impacted by two trends. First, tightly-coupled multiprocessor platforms are becoming quite common. This is evidenced by the availability of affordable symmetric shared-memory multiprocessors and the emergence of multicore architectures. Second, there is an increase in the number of real-time systems that require only soft real-time guarantees and have workloads that necessitate a multiprocessor. Examples of such systems include some tracking, signal-processing, and multimedia systems. Due to the above trends, cost-effective multiprocessor-based soft real-time system designs are of growing importance. Most prior research on real-time scheduling on multiprocessors has focused only on hard real-time systems. In a hard real-time system, no deadline may ever be missed. To meet such stringent timing requirements, all known theoretically optimal scheduling algorithms tend to preempt process threads and migrate them across processors frequently, and also impose certain other restrictions. Hence, the overheads of such algorithms can significantly reduce the amount of useful work that is accomplished and limit their practical implementation. On the other hand, non-optimal algorithms that are more practical suffer from the drawback that their validation tests require workload restrictions that can approach roughly 50% of the available processing capacity. Thus, for soft real-time systems, which can tolerate occasional or bounded deadline misses, and hence, allow for a trade-off between timeliness and improved processor utilization, the existing scheduling algorithms or their validation tests can be overkill. The thesis of this dissertation is: Processor utilization can be improved on multiprocessors while ensuring non-trivial soft real-time guarantees for different soft real-time applications, whose preemption and migration overheads can span different ranges and whose tolerances to tardiness are different, by designing new scheduling algorithms, simplifying optimal ones, and developing new validation tests. The above thesis is established by developing validation tests that are sufficient to provide soft real-time guarantees under non-optimal (but more practical) algorithms, designing and analyzing a new restricted-migration scheduling algorithm, determining the guarantees on timeliness that can be provided when some limiting restrictions of known optimal algorithms are relaxed, and quantifying the benefits of the proposed mechanisms through simulations. First, we show that both preemptive and non-preemptive global earliest-deadline-first(EDF) scheduling can guarantee bounded tardiness (that is, lateness) to every recurrent real-time task system while requiring no restriction on the workload (except that it not exceed the available processing capacity). The tardiness bounds that we derive can be used to devise validation tests for soft real-time systems that are EDF-scheduled. Though overheads due to migrations and other factors are lower under EDF (than under known optimal algorithms), task migrations are still unrestricted. This may be unappealing for some applications, but if migrations are forbidden entirely, then bounded tardiness cannot always be guaranteed. Hence, we consider providing an acceptable middle path between unrestricted-migration and no-migration algorithms, and as a second result, present a new algorithm that restricts, but does not eliminate, migrations. We also determine bounds on tardiness that can be guaranteed under this algorithm. Finally, we consider a more efficient but non-optimal variant of an optimal class of algorithms called Pfair scheduling algorithms. We show that under this variant, called earliest-pseudo-deadline-first (EPDF) scheduling, significantly more liberal restrictions on workloads than previously known are sufficient for ensuring a specified tardiness bound. We also show that bounded tardiness can be guaranteed if some limiting restrictions of optimal Pfair algorithms are relaxed. The algorithms considered in this dissertation differ in the tardiness bounds guaranteed and overheads imposed. Simulation studies show that these algorithms can guarantee bounded tardiness for a significant percentage of task sets that are not schedulable in a hard real-time sense. Furthermore, for each algorithm, conditions exist in which it may be the preferred choice.
BibTeX:
@phdthesis{Devi2006a,
  author = {Devi, UmaMaheswari C.},
  title = {Soft Real--Time Scheduling on Multiprocessors},
  school = {University of North Carolina},
  year = {2006},
  url = {papers/Devi2006a.pdf}
}
Devi, U.C., Leontyev, H. and Anderson, J.H. Efficient Synchronization under Global EDF Scheduling on Multiprocessors 2006 Proceedings of the 18th Euromicro Conference on Real--time Systems (ECRTS), pp. 84-93  inproceedings DOI URL 
Abstract: We consider coordinating accesses to shared data structures in multiprocessor real--time systems scheduled under preemptive global EDF. To our knowledge, prior work on global EDF has focused only on systems of independent tasks. We take an initial step here towards a generic resource-sharing framework by considering simple shared objects, such as queues, stacks, and linked lists. In many applications, the predominate use of synchronization constructs is for sharing such simple objects. We analyze two synchronization methods for such objects, one based on queue-based spin locks and a second based on lock-free algorithms.
BibTeX:
@inproceedings{Devi2006,
  author = {Devi, UmaMaheswari C. and Leontyev, Hennadiy and Anderson, James H.},
  title = {Efficient Synchronization under Global EDF Scheduling on Multiprocessors},
  booktitle = {Proceedings of the 18th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {84--93},
  url = {papers/Devi2006.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2006.10}
}
Dewan, F. and Fisher, N.W. Fixed--Priority Schedulability of Arbitrary-Deadline Sporadic Tasks upon Periodic Resources 2012 Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 358-367  inproceedings DOI URL 
Abstract: Schedulability for compositional real--time systems has been the focus of a great deal of recent research. In this problem domain, we consider the fixed-priority (FP) scheduling of arbitrary-deadline sporadic task systems upon periodic resources. Existing exact or approximate schedulability tests for dedicated uniprocessor scheduling can be used in this setting by modeling the "no-supply period" of the periodic resource model as a special highest priority task. However, the exact schedulability test is highly inefficient from computational perspective, and the straightforward approximate test is pessimistic due to the approximation on the resource unavailability along with the resource demand. In this paper, along with obtaining an exact characterization of schedulability for this setting, we address the need for efficient and effective schedulability results for the large and important class of arbitrary-deadline task systems by deriving a polynomial-time sufficient schedulability algorithm. By simulations, we show that this algorithm performs very well compared with the exact test, and even better than the approximate test.
BibTeX:
@inproceedings{Dewan2012,
  author = {Dewan, Farhana and Fisher, Nathan Wayne},
  title = {Fixed--Priority Schedulability of Arbitrary-Deadline Sporadic Tasks upon Periodic Resources},
  booktitle = {Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {358--367},
  url = {papers/Dewan2012.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2012.54}
}
Dhall, S.K. Scheduling periodic time--critical jobs on single processor and multiprocessor computing systems 1977 School: University of Illinois  phdthesis  
BibTeX:
@phdthesis{Dhall1977,
  author = {Dhall, Sudarshan Kumar},
  title = {Scheduling periodic time--critical jobs on single processor and multiprocessor computing systems},
  school = {University of Illinois},
  year = {1977}
}
Dhall, S.K. and Liu, C.L. On a Real--Time Scheduling Problem 1978 Operations Research
Vol. 26(1), pp. 127-140 
article DOI  
Abstract: We study the problem of scheduling periodic--time-critical tasks on multiprocessor computing systems. A periodic-time-critical task consists of an infinite number of requests, each of which has a prescribed deadline. The scheduling problem is to specify an order in which the requests of a set of tasks are to be executed and the processor to be used, with the goal of meeting all the deadlines with a minimum number of processors. Since the problem of determining the minimum number of processors is difficult, we consider two heuristic algorithms. These are easy to implement and yield a number of processors that is reasonably close to the minimum number. We also analyze the worst-case behavior of these heuristics.
BibTeX:
@article{Dhall1978,
  author = {Dhall, Sudarshan Kumar and Liu, Chung Laung},
  title = {On a Real--Time Scheduling Problem},
  journal = {Operations Research},
  year = {1978},
  volume = {26},
  number = {1},
  pages = {127--140},
  doi = {http://doi.org/10.1287/opre.26.1.127}
}
Di Natale, M. and Stankovic, J.A. Applicability of simulated annealing methods to real--time scheduling and jitter control 1995 Proceedings of the 16th IEEE Real--Time Systems Symposium (RTSS), pp. 190-199  inproceedings DOI URL 
Abstract: This paper presents a non--conventional scheduling approach for distributed static systems where tasks are periodic and have arbitrary deadlines, precedence, and exclusion constraints. The solution presented in this work not only creates feasible schedules, but also minimizes jitter for periodic tasks. The problem of scheduling real-time tasks with minimum jitter is particularly important in many control applications, nevertheless, it has been rarely studied in the scientific literature. We present a general framework consisting of an abstract architecture model and a general programming model. We show how to design a surprisingly simple and flexible scheduling method based on simulated annealing and present some experimental results.
BibTeX:
@inproceedings{DiNatale1995,
  author = {Di Natale, Marco and Stankovic, John A.},
  title = {Applicability of simulated annealing methods to real--time scheduling and jitter control},
  booktitle = {Proceedings of the 16th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1995},
  pages = {190--199},
  url = {papers/DiNatale1995.pdf},
  doi = {http://doi.org/10.1109/REAL.1995.495209}
}
Dibble, P. JSR 282: RTSJ version 1.1 2005   electronic URL 
BibTeX:
@electronic{JSR--282,
  author = {Dibble, Peter},
  title = {JSR 282: RTSJ version 1.1},
  year = {2005},
  url = {http://jcp.org/en/jsr/detail?id=282}
}
Dibble, P. JSR 1: Real--time Specification for Java 1998   electronic URL 
BibTeX:
@electronic{JSR--1,
  author = {Peter Dibble},
  title = {JSR 1: Real--time Specification for Java},
  year = {1998},
  url = {http://jcp.org/en/jsr/detail?id=1}
}
Diessel, O., ElGindy, H., Middendorf, M., Schmeck, H. and Schmidt, B. Dynamic scheduling of tasks on partially reconfigurable FPGAs 2000 IEEE Proceedings on Computers and Digital Techniques
Vol. 147(3), pp. 181-188 
article DOI URL 
Abstract: Field--programmable gate arrays (FPGAs) which allow partial reconfiguration at run time can be shared among multiple independent tasks. When the sequence of tasks to be performed is unpredictable, the FPGA controller needs to make allocation decisions online. Since online allocation suffers from fragmentation, tasks can end up waiting despite there being sufficient, albeit noncontiguous, resources available to service them. The time to complete tasks is consequently longer and the utilisation of the FPGA is lower than it could be. It is proposed that a subset of the tasks executing on the FPGA be rearranged when to do so allows the next pending task to be processed sooner. Methods are described and evaluated for overcoming the NP-hard problems of identifying feasible rearrangements and scheduling the rearrangements when moving tasks are reloaded from off-chip.
BibTeX:
@article{Diessel2000,
  author = {Diessel, Olivier and ElGindy, Hossam and Middendorf, Martin and Schmeck, Hartmut and Schmidt, Bernd},
  title = {Dynamic scheduling of tasks on partially reconfigurable FPGAs},
  journal = {IEEE Proceedings on Computers and Digital Techniques},
  year = {2000},
  volume = {147},
  number = {3},
  pages = {181--188},
  url = {papers/Diessel2000.pdf},
  doi = {http://doi.org/10.1049/ip--cdt:20000485}
}
Dorin, F. Contributions à l'ordonnancement et l'analyse des systèmes temps réel critiques 2010 School: École Nationale Supérieure de Mécanique et d'Aérotechnique  phdthesis URL 
Abstract: Dans nos travaux, nous nous sommes intéressés aux politiques d'ordonnancement en--ligne, pour lesquelles l'ordre d'exécution des tâches est déterminé sur la base des tâches actives dans le système et sans connaissance a priori des tâches qui arriveront dans le futur. Cette problématique s'étend aux réseaux informatiques pour ordonnancer les messages sur le réseau informatique interconnectant les diérents calculateurs du système temps réel. La première contribution concerne le placement et ordonnancement simultanés des tâches dans un système temps réel distribué, permettant de minimiser le nombre de processeurs nécessaires pour respecter les spécications temporelles des tâches. La seconde contribution concerne les tâches à criticité multiple. L'objectif de ce modèle est de prendre en compte la notion de criticité des diérentes tâches, comme par exemple dans la norme DO-178B utilisée en aéronautique. Enn, nous nous sommes intéressés aux systèmes multiprocesseurs ordonnancés par des algorithmes d'ordonnancement semi-partitionné. Cette classe d'algorithme utilise une stratégie par partitionnement pour répartir les tâches parmi les processeurs tout en autorisant la migration des tâches qui ne peuvent pas être aectées à un processeur donné sans violation d'échéance.
BibTeX:
@phdthesis{Dorin2010a,
  author = {Dorin, François},
  title = {Contributions à l'ordonnancement et l'analyse des systèmes temps réel critiques},
  school = {École Nationale Supérieure de Mécanique et d'Aérotechnique},
  year = {2010},
  url = {papers/Dorin2010a.pdf}
}
Dorin, F., Meumeu Yomsi, P., Goossens, J. and Richard, P. Semi--Partitioned Hard Real-Time Scheduling with Restricted Migrations upon Identical Multiprocessor Platforms 2010   unpublished URL 
Abstract: Algorithms based on semi--partitioned scheduling have been proposed as a viable alternative between the two extreme ones based on global and partitioned scheduling. In particular, allowing migration to occur only for few tasks which cannot be assigned to any individual processor, while most tasks are assigned to specific processors, considerably reduces the runtime overhead compared to global scheduling on the one hand, and improve both the schedulability and the system utilization factor compared to partitioned scheduling on the other hand. In this paper, we address the preemptive scheduling problem of hard real-time systems composed of sporadic constrained-deadline tasks upon identical multiprocessor platforms. We propose a new algorithm and a scheduling paradigm based on the concept of semi-partitioned scheduling with restricted migrations in which jobs are not allowed to migrate, but two subsequent jobs of a task can be assigned to different processors by following a periodic strategy.
BibTeX:
@unpublished{Dorin2010,
  author = {Dorin, François and Meumeu Yomsi, Patrick and Goossens, Joël and Richard, Pascal},
  title = {Semi--Partitioned Hard Real-Time Scheduling with Restricted Migrations upon Identical Multiprocessor Platforms},
  year = {2010},
  url = {papers/Dorin2010.pdf}
}
Duda, K.J. and Cheriton, D.R. Borrowed-virtual-time (BVT) Scheduling: Supporting Latency-sensitive Threads in a General-purpose Scheduler 1999 SIGOPS Operating Systems Review
Vol. 33(5), pp. 261-276 
article DOI URL 
Abstract: Systems need to run a larger and more diverse set of applications, from real-time to interactive to batch, on uniprocessor and multiprocessor platforms. However, most schedulers either do not address latency requirements or are specialized to complex real-time paradigms, limiting their applicability to general-purpose systems.In this paper, we present Borrowed-Virtual-Time (BVT) Scheduling, showing that it provides low-latency for real-time and interactive applications yet weighted sharing of the CPU across applications according to system policy, even with thread failure at the real-time level, all with a low-overhead implementation on multiprocessors as well as uniprocessors. It makes minimal demands on application developers, and can be used with a reservation or admission control module for hard real-time applications.
BibTeX:
@article{Duda1999,
  author = {Duda, Kenneth J. and Cheriton, David R.},
  title = {Borrowed-virtual-time (BVT) Scheduling: Supporting Latency-sensitive Threads in a General-purpose Scheduler},
  journal = {SIGOPS Operating Systems Review},
  publisher = {ACM},
  year = {1999},
  volume = {33},
  number = {5},
  pages = {261--276},
  url = {/papers/Duda1999.pdf},
  doi = {http://doi.org/10.1145/319344.319169}
}
Easwaran, A. and Andersson, B. Resource Sharing in Global Fixed--Priority Preemptive Multiprocessor Scheduling 2009 Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS), pp. 377-386  inproceedings DOI URL 
Abstract: In this paper we consider global fixed--priority preemptive multiprocessor scheduling of constrained-deadline sporadic tasks that share resources in a non-nested manner. We develop a novel resource-sharing protocol and a corresponding schedulability test for this system. We also develop the first schedulability analysis of priority inheritance protocol for the aforementioned system. Finally, we show that these protocols are efficient (based on the developed schedulability tests) for a class of priority-assignments called reasonable priority-assignments.
BibTeX:
@inproceedings{Easwaran2009,
  author = {Easwaran, Arvind and Andersson, Björn},
  title = {Resource Sharing in Global Fixed--Priority Preemptive Multiprocessor Scheduling},
  booktitle = {Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {377--386},
  url = {papers/Easwaran2009.pdf},
  doi = {http://doi.org/10.1109/RTSS.2009.37}
}
Easwaran, A. and Andersson, B. Resource Sharing in Global Fixed--Priority Preemptive Multiprocessor Scheduling 2009 (HURRAY-TR-090908)School: Polytechnic Institute of Porto (ISEP--IPP)  techreport URL 
Abstract: In this paper we consider global fixed--priority preemptive multiprocessor scheduling of constrained-deadline sporadic tasks that share resources in a non-nested manner. We develop a novel resource-sharing protocol and a corresponding schedulability test for this system. We also develop the first schedulability analysis of priority inheritance protocol for the aforementioned system. Finally, we show that these protocols are efficient (based on the developed schedulability tests) for a class of priority-assignments called reasonable priority-assignments.
BibTeX:
@techreport{Easwaran2009a,
  author = {Easwaran, Arvind and Andersson, Björn},
  title = {Resource Sharing in Global Fixed--Priority Preemptive Multiprocessor Scheduling},
  school = {Polytechnic Institute of Porto (ISEP--IPP)},
  year = {2009},
  number = {HURRAY--TR-090908},
  url = {papers/Easwaran2009a.pdf}
}
Echtle, K. and Eusgeld, I. A Genetic Algorithm for Fault--Tolerant System Design 2003 Dependable Computing
Vol. 2847Dependable Computing, pp. 197-213 
incollection DOI URL 
Abstract: Due to high cost, considerable complexity and long design cycles of fault--tolerant systems, a (partial) automation of the design process becomes attractive. This paper presents an approach to automatic design by use of a genetic algorithm. Unlike typical genetic algorithms the individuals (which represent a fault-tolerant system structure each) are represented by a non-cyclic graph rather than a string. Special crossover and mutation operations modify the individuals such that reasonable fault-tolerant systems are likely to be generated. The biggest problem in using genetic algorithms lies in the definition of an appropriate fitness function one has to apply to each of the many generated individuals. A complete analysis of a single fault-tolerant system would comprise time-consuming fault-tree analysis, reachability analysis of the state space, etc. A substantial speed-up by orders of magnitude has been achieved by the development of a completely new fitness function, which can be considered as a simplified reachability analysis. For many fault tolerance techniques it visits each component only once (or very few times in the case of mechanisms like rollback, retry etc.).
BibTeX:
@incollection{Echtle2003,
  author = {Echtle, Klaus and Eusgeld, Irene},
  title = {A Genetic Algorithm for Fault--Tolerant System Design},
  booktitle = {Dependable Computing},
  journal = {Dependable Computing},
  publisher = {Springer Berlin / Heidelberg},
  year = {2003},
  volume = {2847},
  pages = {197--213},
  url = {papers/Echtle2003.pdf},
  doi = {http://doi.org/10.1007/978--3-540-45214-0_16}
}
Ekberg, P. and Yi, W. Bounding and shaping the demand of generalized mixed--criticality sporadic task systems 2014 Real--Time Systems
Vol. 50(1), pp. 48-86 
article DOI URL 
Abstract: We derive demand--bound functions for mixed-criticality sporadic tasks, and use these to determine EDF-schedulability. Tasks have different demand-bound functions for each criticality mode. We show how to shift execution demand from high-to low-criticality mode by tuning the relative deadlines. This allows us to shape the demand characteristics of each task. We propose an efficient algorithm for tuning all relative deadlines of a task set in order to shape the total demand to the available supply of the computing platform. Experiments indicate that this approach is significantly more powerful than previous approaches to mixed-criticality scheduling. This new approach has the added benefit of supporting hierarchical scheduling frameworks.
BibTeX:
@article{Ekberg2014,
  author = {Ekberg, Pontus and Yi, Wang},
  title = {Bounding and shaping the demand of generalized mixed--criticality sporadic task systems},
  journal = {Real--Time Systems},
  year = {2014},
  volume = {50},
  number = {1},
  pages = {48--86},
  url = {papers/Ekberg2014.pdf},
  doi = {http://doi.org/10.1007/s11241--013-9187-z}
}
Ekberg, P. and Yi, W. Bounding and Shaping the Demand of Mixed--Criticality Sporadic Tasks 2012 Proceedings of the 24th Euromicro Conference on Real--Time Systems (ECRTS), pp. 135-144  inproceedings DOI URL 
Abstract: We derive demand--bound functions for mixed-criticality sporadic tasks, and use these to determine EDF-schedulability. Tasks have different demand-bound functions for each criticality mode. We show how to shift execution demand from high-to low-criticality mode by tuning the relative deadlines. This allows us to shape the demand characteristics of each task. We propose an efficient algorithm for tuning all relative deadlines of a task set in order to shape the total demand to the available supply of the computing platform. Experiments indicate that this approach is significantly more powerful than previous approaches to mixed-criticality scheduling. This new approach has the added benefit of supporting hierarchical scheduling frameworks.
BibTeX:
@inproceedings{Ekberg2012,
  author = {Ekberg, Pontus and Yi, Wang},
  title = {Bounding and Shaping the Demand of Mixed--Criticality Sporadic Tasks},
  booktitle = {Proceedings of the 24th Euromicro Conference on Real--Time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {135--144},
  url = {papers/Ekberg2012.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2012.24}
}
Elliott, G.A. and Anderson, J.H. Exploring the Multitude of Real--Time Multi-GPU Configurations 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 260-271  inproceedings DOI URL 
Abstract: Motivated by computational capacity and power efficiency, techniques for integrating graphics processing units (GPUs) into real--time systems have become an active area of research. While much of this work has focused on single-GPU systems, multiple GPUs may be used for further benefits. Similar to CPUs in multiprocessor systems, GPUs in multi-GPU systems may be managed using partitioned, clustered, or global methods, independent of CPU organization. This gives rise to many combinations of CPU/GPU organizational methods that, when combined with additional GPU management options, results in thousands of “reasonable” configuration choices. In this paper, we explore real-time schedulability of several categories of configurations for multiprocessor, multi-GPU systems that are possible under GPUSync, a recently proposed highly configurable real-time GPU management framework. Our analysis includes the careful consideration of GPU-related overheads. We show system configuration strongly affects real-time schedulability. We also identify which configurations offer the best schedulability in order to guide the implementation of GPU-based real-time systems and future research.
BibTeX:
@inproceedings{Elliott2014,
  author = {Elliott, Glenn A. and Anderson, James H.},
  title = {Exploring the Multitude of Real--Time Multi-GPU Configurations},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {260--271},
  url = {papers/Elliott2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.39}
}
Emberson, P. Searching For Flexible Solutions To Task Allocation Problems 2009 School: University of York  phdthesis URL 
Abstract: Consumers of modern avionics and automotive systems expect many, well integrated features. Efforts are continually being made to make engineering processes better equipped to adapt to enhancement requests. Within both the avionics and automotive industries, standardisation of hardware and interfaces has allowed software to be mapped to hardware at a later stage of the design process and for this mapping to be more easily changed. Tools which automatically perform the mapping of tasks and messages onto a hardware platform are called task allocation tools. The primary requirement of a task allocation tool for hard real--time systems is to find a mapping and schedule such that all tasks and messages respond before their deadlines. However, there are other qualities which can be used to further differentiate between solutions, two of the most important being exibility and adaptability. This thesis builds on previous task allocation work by extending a heuristic search algorithm to produce solutions with improved flexibility. Inspiration is drawn from scenario based architecture analysis methods. These methods interrogate an architecture model to see how it will react to different change scenarios. This idea is used within a search algorithm to encourage it to produce solutions which can meet the needs of provided scenarios with no or very few changes. It is shown that these solutions are also more flexible with respect to upgrades which differ from the scenarios. Run-time adaptability is another quality which can be affected by the choice of task allocation. Real-time systems can specify multiple task sets representing different modes of operation. The system will switch between modes at run-time to adapt to environmental changes and must do so efficiently. The task allocation algorithm is adapted for multi-moded systems and it is shown that solutions can be found which allow the system to transition between modes with minimal disruption. Safety-critical real-time systems have become dependent on software to provide critical functionality such as fly-by-wire control and engine emission regulation. These systems must be fault-tolerant and support graceful degradation, another form of adaptability. In the final part of this thesis, the task allocation algorithm is modified to select a number of replicas for each task as well as their allocation so that the system can withstand as many processor failures as possible before the level of service provided by the system falls below a safe threshold.
BibTeX:
@phdthesis{Emberson2009,
  author = {Emberson, Paul},
  title = {Searching For Flexible Solutions To Task Allocation Problems},
  school = {University of York},
  year = {2009},
  url = {papers/Emberson2009.pdf}
}
Emberson, P. and Bate, I. Extending a Task Allocation Algorithm for Graceful Degradation of Real--Time Distributed Embedded Systems 2008 Proceedings of the 29th IEEE Real--Time Systems Symposium (RTSS), pp. 270-279  inproceedings DOI URL 
Abstract: Previous research which has considered task allocation and fault--tolerance together has concentrated on constructing schedules which accommodate a fixed number of redundant tasks. Often, all faults are treated as being equally severe. There is little work which combines task allocation with architectural level fault-tolerance issues such as the number of replicas to use and how they should be configured, both of which are tackled by this work. An accepted method for assessing the impact of a combination of faults is to build a system utility model which can be used to assess how the system degrades when components fail. The key challenge addressed here is how to design objective functions based on a utility model which can be incorporated into a search algorithm in order to optimise fault-tolerance properties. Other issues such as how to extend the local search neighbourhood and balance objectives with schedulability constraints are also discussed.
BibTeX:
@inproceedings{Emberson2008,
  author = {Emberson, Paul and Bate, Iain},
  title = {Extending a Task Allocation Algorithm for Graceful Degradation of Real--Time Distributed Embedded Systems},
  booktitle = {Proceedings of the 29th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {270--279},
  url = {papers/Emberson2008.pdf},
  doi = {http://doi.org/10.1109/RTSS.2008.24}
}
Faggioli, D., Checconi, F., Trimarchi, M. and Scordino, C. An EDF scheduling class for the Linux kernel 2009 Proceedings of the 11th Real Time Linux Workshop (RTLW), pp. 8 pp.  inproceedings URL 
Abstract: The Linux kernel is mainly used is general--purpose operating system, i.e., in server and/or desktop environments. During the last years, however, academic institutions and companies showed an increasing interest in using it for real-time and control applications as well. However, since Linux has not been designed to be a real-time operating, the best-effort scheduling policy is not suited to provide high utilization and strong guarantees to time-sensitive tasks. We present an enhancement of the Linux scheduler through the implementation of the well known Earliest Deadline First algorithm for real-time tasks, leaving the current behavior of existing policies unchanged. It is integrated with the latest Linux scheduler, support multicore platforms, it is available for embedded architectures (like ARM) and can be used with either periodic or aperiodic workloads.
BibTeX:
@inproceedings{Faggioli2009,
  author = {Faggioli, Dario and Checconi, Fabio and Trimarchi, Michael and Scordino, Claudio},
  title = {An EDF scheduling class for the Linux kernel},
  booktitle = {Proceedings of the 11th Real Time Linux Workshop (RTLW)},
  year = {2009},
  pages = {8 pp.},
  url = {papers/Faggioli2009.pdf}
}
Faggioli, D., Lipari, G. and Cucinotta, T. The Multiprocessor Bandwidth Inheritance Protocol 2010 Proceedings of the 22nd Euromicro Conference on Real--Time Systems (ECRTS), pp. 90-99  inproceedings DOI URL 
Abstract: In this paper, the Multiprocessor Bandwidth Inheritance (M--BWI) protocol is presented, which constitutes an extension of the Bandwidth Inheritance (BWI) protocol to symmetric multiprocessor and multicore systems. Similarly to priority inheritance, M-BWI reduces priority inversion in reservation-based scheduling systems, it allows the coexistence of hard, soft and non-real-time tasks, it does not require any information on the temporal parameters of the tasks, hence, it is particularly suitable to open systems, where tasks can dynamically arrive and leave, and their temporal parameters are unknown or only partially known. Moreover, if it is possible to estimate such parameters as the worst-case execution time and the critical sections length, then it is possible to compute an upper bound to the task blocking time. Finally, the M-BWI protocol is neutral to the underlying scheduling scheme, since it can be implemented both in global and partitioned scheduling schemes.
BibTeX:
@inproceedings{Faggioli2010,
  author = {Faggioli, Dario and Lipari, Giuseppe and Cucinotta, Tommaso},
  title = {The Multiprocessor Bandwidth Inheritance Protocol},
  booktitle = {Proceedings of the 22nd Euromicro Conference on Real--Time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {90--99},
  url = {papers/Faggioli2010.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2010.19}
}
Faggioli, D., Trimarchi, M. and Checconi, F. An Implementation of the Earliest Deadline First Algorithm in Linux 2009 Proceedings of 24th ACM Symposium on Applied Computing (SAC), pp. 1984-1989  inproceedings DOI URL 
Abstract: Recently, many projects have been started to introduce some real--time mechanisms into general purpose operating systems (GPOS) in order to make them capable of providing the users with some temporal guarantees. Many of these projects focused especially on Linux for its capillary and widespread adoption throughout many different research and industrial environments. By tracking the kernel release cycle, we propose an efficient Earliest Deadline First implementation in the form of a patch-set against the 2.6.27 version, that is the latest released one, as of now. Our implementation provides the user with the possibility to choose SCHED EDF as one of the possible scheduling policies for a task, with an enhanced version of the standard algorithm. In fact, we propose a new approach to shared resources’ access which, differently from many other previous existing works, does not require the user to specify any parameters about the critical sections every task will enter during its execution.
BibTeX:
@inproceedings{Faggioli2009a,
  author = {Faggioli, Dario and Trimarchi, Michael and Checconi, Fabio},
  title = {An Implementation of the Earliest Deadline First Algorithm in Linux},
  booktitle = {Proceedings of 24th ACM Symposium on Applied Computing (SAC)},
  year = {2009},
  pages = {1984--1989},
  url = {papers/Faggioli2009a.pdf},
  doi = {http://doi.org/10.1145/1529282.1529723}
}
Fauberteau, F. Sûreté temporelle pour les systèmes temps réel multiprocesseurs 2011 School: Université Paris--Est  phdthesis URL 
Abstract: The hard real--time systems are characterized by sets of tasks for which are known the deadline, the arrival model (frequency) and the Worst-Case Execution Time (WCET). We focus on the scheduling of these systems on multiprocessor platforms. One of the main issues of this topic is to ensure that all deadlines are met. We go further by focusing on the temporal safety which we characterized by the properties of (i) robustness and (ii) sustainability. The robustness consists in providing an interval on the increases of (i-a) WCET and (i-b) frequency in such a way that the deadlines are met. The sustainability consists in ensuring that no deadline is missed when the following constraints are relaxed : (ii-a) WCET (decreasing), (ii-b) frequency (decreasing) and (ii-c) deadline (increasing). The robustness amounts to tolerate unexpected behaviors while the sustainability is the guarantee that the scheduling algorithm does not suffer from anomalies because of a relaxation of constraints. We consider fixed-priority scheduling for which any job of a task is scheduled with the same priority. Firstly, we study the property of robustness in off-line scheduling approaches without migration (partitioning). We deal with the case of tasks with or without shared resources. Secondly, we study the property of sustainability of an online restricted-migration scheduling approach without shared resources.
BibTeX:
@phdthesis{Fauberteau2011e,
  author = {Fauberteau, Frédéric},
  title = {Sûreté temporelle pour les systèmes temps réel multiprocesseurs},
  school = {Université Paris--Est},
  year = {2011},
  url = {tel.archives-ouvertes.fr/docs/00/66/85/37/PDF/manuscrit.pdf}
}
Fauberteau, F., George, L., Masson, D. and Midonnet, S. Ordonnancement multiprocesseur global basé sur la laxité avec migrations restreintes 2011 Proceedings of the 12th Congrès Annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision (ROADEF), pp. 47-48  inproceedings URL 
BibTeX:
@inproceedings{Fauberteau2011,
  author = {Fauberteau, Frédéric and George, Laurent and Masson, Damien and Midonnet, Serge},
  title = {Ordonnancement multiprocesseur global basé sur la laxité avec migrations restreintes},
  booktitle = {Proceedings of the 12th Congrès Annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision (ROADEF)},
  year = {2011},
  pages = {47--48},
  url = {papers/Fauberteau2011.pdf}
}
Fauberteau, F. and Midonnet, S. Sustainability in static--priority restricted-migration scheduling 2012 Proceedings of the 2012 Research in Applied Computation Symposium (RACS), pp. 6  inproceedings  
BibTeX:
@inproceedings{Fauberteau2012,
  author = {Fauberteau, Frédéric and Midonnet, Serge},
  title = {Sustainability in static--priority restricted-migration scheduling},
  booktitle = {Proceedings of the 2012 Research in Applied Computation Symposium (RACS)},
  publisher = {ACM},
  year = {2012},
  pages = {6}
}
Fauberteau, F. and Midonnet, S. Robust Partitioning for Real--Time Multiprocessor Systems with Shared Resources 2011 Proceedings of the 2011 Research in Applied Computation Symposium (RACS), pp. 71-76  inproceedings DOI URL 
Abstract: In this paper, we focus on the temporal robustness in the hard real--time multiprocessor systems. This robustness is the capacity to tolerate faults in such a way that no deadlines are missed. A model of sporadic and dependent tasks is considered. Our contribution is to propose a partitioning algorithm which assigns the tasks to processors in order to maximize the robustness of the system to Worst Case Execution Time (WCET) overruns faults or Minimum Inter-arrival Time (MIT) violations.
BibTeX:
@inproceedings{Fauberteau2011d,
  author = {Fauberteau, Frédéric and Midonnet, Serge},
  title = {Robust Partitioning for Real--Time Multiprocessor Systems with Shared Resources},
  booktitle = {Proceedings of the 2011 Research in Applied Computation Symposium (RACS)},
  publisher = {ACM},
  year = {2011},
  pages = {71--76},
  url = {papers/Fauberteau2011d.pdf},
  doi = {http://doi.org/10.1145/2103380.2103394}
}
Fauberteau, F. and Midonnet, S. Structure de données pour systèles temps--réel multiprocesseur : l'exemple des arbres rouge-noirs 2009 Proceedings of the 3rd Workshop sur la Cohérence des données en Univers Réparti (CDUR), pp. 7-10  inproceedings URL 
BibTeX:
@inproceedings{Fauberteau2009b,
  author = {Fauberteau, Frédéric and Midonnet, Serge},
  title = {Structure de données pour systèles temps--réel multiprocesseur : l'exemple des arbres rouge-noirs},
  booktitle = {Proceedings of the 3rd Workshop sur la Cohérence des données en Univers Réparti (CDUR)},
  year = {2009},
  pages = {7--10},
  url = {http://hal--univ-mlv.archives-ouvertes.fr/docs/00/62/03/94/PDF/hal.pdf}
}
Fauberteau, F. and Midonnet, S. Worst case analysis of TreeMap data structure 2008 Proceedings of the 2nd Junior Researcher Workshop on Real--Time Computing (JRWRTC), pp. 33-36  inproceedings  
BibTeX:
@inproceedings{Fauberteau2008,
  author = {Fauberteau, Frédéric and Midonnet, Serge},
  title = {Worst case analysis of TreeMap data structure},
  booktitle = {Proceedings of the 2nd Junior Researcher Workshop on Real--Time Computing (JRWRTC)},
  year = {2008},
  pages = {33--36}
}
Fauberteau, F., Midonnet, S. and George, L. Laxity--Based Restricted-Migration Scheduling 2011 Proceedings of the 16th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA), pp. 1-8  inproceedings DOI URL 
Abstract: We focus on the real--time multiprocessor scheduling of periodic tasksets. We propose a new static priority scheduling algorithm based on the restricted-migration approach. Restricted-migration approach is a global scheduling approach for which the number of migrations is bounded just by one migration per job at most. Our algorithm uses the laxity of already admitted jobs to decide the admission of newly arrived jobs. We prove that this algorithm is predictable. We give a feasible interval and we propose a utilization bound for this algorithm. We also compare our algorithm to other global algorithms in terms of schedulability by simulations.
BibTeX:
@inproceedings{Fauberteau2011b,
  author = {Fauberteau, Frédéric and Midonnet, Serge and George, Laurent},
  title = {Laxity--Based Restricted-Migration Scheduling},
  booktitle = {Proceedings of the 16th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA)},
  publisher = {IEEE Computer Society},
  year = {2011},
  pages = {1--8},
  url = {papers/Fauberteau2011b.pdf},
  doi = {http://doi.org/10.1109/ETFA.2011.6059012}
}
Fauberteau, F., Midonnet, S. and George, L. A Robust Partitioned Scheduling for Real--Time Multiprocessor Systems 2010 Proceedings of the 7th IFIP Conference on Distributed and Parallel Embedded Systems (DIPES), pp. 193-204  inproceedings URL 
BibTeX:
@inproceedings{Fauberteau2010,
  author = {Fauberteau, Frédéric and Midonnet, Serge and George, Laurent},
  title = {A Robust Partitioned Scheduling for Real--Time Multiprocessor Systems},
  booktitle = {Proceedings of the 7th IFIP Conference on Distributed and Parallel Embedded Systems (DIPES)},
  publisher = {Springer Science and Business Media},
  year = {2010},
  pages = {193--204},
  url = {papers/Fauberteau2010.pdf}
}
Fauberteau, F., Midonnet, S. and George, L. Improvement of schedulability bound by task splitting in partitioning scheduling 2010 Proceedings of the 1st International Real--Time Scheduling Open Problems Seminar (RTSOPS), pp. 20-21  inproceedings URL 
Abstract: We focus on the class of static--priority partitioning scheduling algorithm on multiprocessor. We are interested in improving the schedulability of these algorithms by splitting the tasks which cannot be successfully allocated on processors.
BibTeX:
@inproceedings{Fauberteau2010a,
  author = {Fauberteau, Frédéric and Midonnet, Serge and George, Laurent},
  title = {Improvement of schedulability bound by task splitting in partitioning scheduling},
  booktitle = {Proceedings of the 1st International Real--Time Scheduling Open Problems Seminar (RTSOPS)},
  year = {2010},
  pages = {20--21},
  url = {papers/Fauberteau2009a.pdf}
}
Fauberteau, F., Midonnet, S. and George, L. Robust Partitioned Scheduling for Static--Priority Real-Time Multiprocessor Systems with Shared Resources 2010 Proceedings of the 18th International Conference on Real--Time and Network Systems (RTNS), pp. 217-225  inproceedings URL 
Abstract: We focus on the partitioned scheduling of sporadic real--time tasks with constrained deadlines. The scheduling policy on each processor is static-priority. The considered tasks are not independent and the consistency of these shared data is ensured by a multiprocessor synchronization protocol. Considering these assumptions, we propose a partitioned scheduling algorithm which tends to maximize the robustness of the tasks to the Worst Case Execution Time (WCET) overruns faults. We describe the context of the problem and we outline our solution based on simulated annealing.
BibTeX:
@inproceedings{Fauberteau2010b,
  author = {Fauberteau, Frédéric and Midonnet, Serge and George, Laurent},
  title = {Robust Partitioned Scheduling for Static--Priority Real-Time Multiprocessor Systems with Shared Resources},
  booktitle = {Proceedings of the 18th International Conference on Real--Time and Network Systems (RTNS)},
  year = {2010},
  pages = {217--225},
  url = {http://hal--univ-mlv.archives-ouvertes.fr/docs/00/62/03/69/PDF/hal.pdf}
}
Fauberteau, F., Midonnet, S. and George, L. Allowance--Fit: A Partitioning Algorithm for Temporal Robustness of Hard Real-Time Systems upon Multiprocessors 2009 Proceedings of the Work--in-Progress Session of the 14th IEEE International Conference on Emerging Technologies and Factory Automation (WiP ETFA), pp. 4pp  inproceedings DOI URL 
Abstract: We consider in this paper a partitioned real--time multiprocessor scheduling problem for sporadic task having constrained deadlines and a fixed priority scheduling. A major problem with partitioned scheduling is to determine if there exists a valid partitioning satisfying all the tasks deadlines. Many algorithms have tried to solve this problem. Most of them have considered First Fit Partitioning to minimize the number of processors required at the price of maximizing the load on each assigned processors. In this paper, we propose another partitioning strategy that aims at maximizing the allowance of WCETs of the tasks defined as the maximum extra duration that can be given to a task without compromising the task deadlines. The Allowance-Fit partitioning we propose uses the allowance criteria. We show that the partition found by our algorithm improves the temporal robustness of all the tasks of the system in the case of WCET overruns faults.
BibTeX:
@inproceedings{Fauberteau2009,
  author = {Fauberteau, Frédéric and Midonnet, Serge and George, Laurent},
  title = {Allowance--Fit: A Partitioning Algorithm for Temporal Robustness of Hard Real-Time Systems upon Multiprocessors},
  booktitle = {Proceedings of the Work--in-Progress Session of the 14th IEEE International Conference on Emerging Technologies and Factory Automation (WiP ETFA)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {4pp},
  url = {papers/Fauberteau2009.pdf},
  doi = {http://doi.org/10.1109/ETFA.2009.5347249}
}
Fauberteau, F., Midonnet, S. and Istrate, D. Power Saving of Real Time Embedded Sensor for Medical Remote Monitoring 2009 Proceedings of the 4th International Conference on Systems (ICONS), pp. 63-67  inproceedings DOI URL 
BibTeX:
@inproceedings{Fauberteau2009a,
  author = {Fauberteau, Frédéric and Midonnet, Serge and Istrate, Dan},
  title = {Power Saving of Real Time Embedded Sensor for Medical Remote Monitoring},
  booktitle = {Proceedings of the 4th International Conference on Systems (ICONS)},
  publisher = {IEEE Computer Society Press},
  year = {2009},
  pages = {63--67},
  url = {papers/Fauberteau2009a.pdf},
  doi = {http://doi.org/10.1109/ICONS.2009.47}
}
Fauberteau, F., Midonnet, S. and Qamhieh, M. Partitioned Scheduling of Parallel Real--time Tasks on Multiprocessor Systems 2011 Proceedings of the Work--in-Progress Session of the 23rd Euromicro Conference on Real-Time Systems (WiP ECRTS), pp. 4pp  inproceedings URL 
Abstract: In this paper, we focus on the scheduling of periodic fork--join real-time tasks on multiprocessor systems. Parallel real-time tasks in the fork-join model have strict parallel segments without laxity. We propose a partitioned scheduling algorithm which increases the laxity of the parallel segments and therefore the schedulability of tasksets of this model. A similar algorithm has been proposed in the literature but it produces job migrations. Our algorithm eliminates the use of job migrations in order to create a portable algorithm that can be implemented on a standard Linux kernel. Results of extensive simulations are provided in order to analyze the schedulability of the proposed algorithm, and to provide comparisons with the other algorithm proposed in the literature.
BibTeX:
@inproceedings{Fauberteau2011a,
  author = {Fauberteau, Frédéric and Midonnet, Serge and Qamhieh, Manar},
  title = {Partitioned Scheduling of Parallel Real--time Tasks on Multiprocessor Systems},
  booktitle = {Proceedings of the Work--in-Progress Session of the 23rd Euromicro Conference on Real-Time Systems (WiP ECRTS)},
  year = {2011},
  pages = {4pp},
  url = {papers/Fauberteau2011a.pdf}
}
Fauberteau, F., Midonnet, S. and Qamhieh, M. Partitioned Scheduling of Parallel Real--time Tasks on Multiprocessor Systems 2011 ACM SIGBED Review
Vol. 8(3), pp. 4pp 
article DOI URL 
Abstract: In this paper, we focus on the scheduling of periodic fork--join real-time tasks on multiprocessor systems. Parallel real-time tasks in the fork-join model have strict parallel segments without laxity. We propose a partitioned scheduling algorithm which increases the laxity of the parallel segments and therefore the schedulability of tasksets of this model. A similar algorithm has been proposed in the literature but it produces job migrations. Our algorithm eliminates the use of job migrations in order to create a portable algorithm that can be implemented on a standard Linux kernel. Results of extensive simulations are provided in order to analyze the schedulability of the proposed algorithm, and to provide comparisons with the other algorithm proposed in the literature.
BibTeX:
@article{Fauberteau2011c,
  author = {Fauberteau, Frédéric and Midonnet, Serge and Qamhieh, Manar},
  title = {Partitioned Scheduling of Parallel Real--time Tasks on Multiprocessor Systems},
  journal = {ACM SIGBED Review},
  year = {2011},
  volume = {8},
  number = {3},
  pages = {4pp},
  note = {Special Issue on Work--in-Progress (WiP) session of the 23rd Euromicro Conference on Real-Time Systems (ECRTS 2011)},
  url = {http://sigbed.seas.upenn.edu/archives/2011--09/06_fauberteau.pdf},
  doi = {http://doi.org/10.1145/2038617.2038623}
}
Feitelson, D.G. and Rudolph, L. Gang scheduling performance benefits for fine--grain synchronization 1992 Journal of Parallel and Distributed Computing
Vol. 16(4), pp. 306-318 
article DOI URL 
Abstract: Multiprogrammed multiprocessors executing fine--grain parallel programs appear to require new scheduling policies. A promising new idea is gang scheduling, where a set of threads are scheduled to execute simultaneously on a set of processors. This has the intuitive appeal of supplying the threads with an environment that is very similar to a dedicated machine. It allows the threads to interact efficiently by using busy waiting, without the risk of waiting for a thread that currently is not running. Without gang scheduling, threads have to block in order to synchronize, thus suffering the overhead of a context switch. While this is tolerable in coarse-grain computations, and might even lead to performance benefits if the threads are highly unbalanced, it causes severe performance degradation in the fine-grain case. We have developed a model to evaluate the performance of different combinations of synchronization mechanisms and scheduling policies, and validated it by an implementation on the Makbilan multiprocessor. The model leads to the conclusion that gang scheduling is required for efficient fine-grain synchronization on multiprogrammed multiprocessors.
BibTeX:
@article{Feitelson1992,
  author = {Feitelson, Dror G. and Rudolph, Larry},
  title = {Gang scheduling performance benefits for fine--grain synchronization},
  journal = {Journal of Parallel and Distributed Computing},
  year = {1992},
  volume = {16},
  number = {4},
  pages = {306--318},
  url = {papers/Feitelson1992.pdf},
  doi = {http://doi.org/10.1016/0743--7315(92)90014-E}
}
Felser, M. Real--Time Ethernet - Industry Prospective 2005 Proceedings of the IEEE
Vol. 93(6), pp. 1118-1129 
article DOI URL 
Abstract: After more than ten years of experience with applications of fieldbus in automation technology, the industry has started to develop and adopt Real--Time Ethernet (RTE) solutions. There already exists now more than ten proposed solutions. International Electrotechnical Commission standards are trying to give a guideline and selection criteria based on recognized indicators for the user.
BibTeX:
@article{Felser2005,
  author = {Felser, Max},
  title = {Real--Time Ethernet - Industry Prospective},
  journal = {Proceedings of the IEEE},
  year = {2005},
  volume = {93},
  number = {6},
  pages = {1118--1129},
  url = {papers/Felser2005.pdf},
  doi = {http://doi.org/10.1109/JPROC.2005.849720}
}
Fisher, N., Chen, J.-J., Wang, S. and Thiele, L. Thermal--Aware Global Real-Time Scheduling on Multicore Systems 2009 Proceedings of the 15th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS), pp. 131-140  inproceedings DOI URL 
Abstract: As the power density of modern electronic circuits increases dramatically, systems are prone to overheating. Thermal management has become a prominent issue in system design. This paper explores thermal--aware scheduling for sporadic real-time tasks to minimize the peak temperature in a homogeneous multicore system, in which heat might transfer among some cores. By deriving an ideally preferred speed for each core, we propose global scheduling algorithms which can exploit the flexibility of multicore platforms at low temperature. Compared with load-balancing strategies, the proposed algorithms can significantly reduce the peak temperature by up to 30°C to 70°C for simulated platforms.
BibTeX:
@inproceedings{Fisher2009,
  author = {Fisher, Nathan and Chen, Jian--Jia and Wang, Shengquan and Thiele, Lothar},
  title = {Thermal--Aware Global Real-Time Scheduling on Multicore Systems},
  booktitle = {Proceedings of the 15th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {131--140},
  url = {papers/Fisher2009.pdf},
  doi = {http://doi.org/10.1109/RTAS.2009.34}
}
Fisher, N.W. The Multiprocessor Real--Time Scheduling of General Task Systems 2007 School: University of North Carolina at Chapel Hill  phdthesis URL 
Abstract: The recent emergence of multicore and related technologies in many commercial systems has increased the prevalence of multiprocessor architectures. Contemporaneously, real--time applications have become more complex and sophisticated in their behavior and interaction. Inevitably, these complex real-time applications will be deployed upon these multiprocessor platforms and require temporal analysis techniques to verify their correctness. However, most prior research in multiprocessor real-time scheduling has addressed the temporal analysis only of Liu and Layland task systems. The goal of this dissertation is to extend real-time scheduling theory for multiprocessor systems by developing temporal analysis techniques for more general task models such as the sporadic task model, the generalized multiframe task model, and the recurring real-time task model. The thesis of this dissertation is: Optimal online multiprocessor real-time scheduling algorithms for sporadic and more general task systems are impossible; however, efficient, online scheduling algorithms and associated feasibility and schedulability tests, with provably bounded deviation from any optimal test, exist. To support our thesis, this dissertation develops feasibility and schedulability tests for various multiprocessor scheduling paradigms. We consider three classes of multiprocessor scheduling based on whether a real-time job may migrate between processors: full-migration, restricted-migration, and partitioned. For all general task iii systems, we obtain feasibility tests for arbitrary real-time instances under the full- and restricted-migration paradigms. Despite the existence of tests for feasibility, we show that optimal online scheduling of sporadic and more general systems is impossible. Therefore, we focus on scheduling algorithms that have constant-factor approximation ratios in terms of an analysis technique known as resource augmentation. We develop schedulability tests for scheduling algorithms, earliest-deadline-first (edf) and deadline-monotonic (dm), under full-migration and partitioned scheduling paradigms. Feasibility and schedulability tests presented in this dissertation use the workload metrics of demand-based load and maximum job density and have provably bounded deviation from optimal in terms of resource augmentation. We show the demand-based load and maximum job density metrics may be exactly computed in pseudo-polynomial time for general task systems and approximated in polynomial time for sporadic task systems.
BibTeX:
@phdthesis{Fisher2007a,
  author = {Fisher, Nathan Wayne},
  title = {The Multiprocessor Real--Time Scheduling of General Task Systems},
  school = {University of North Carolina at Chapel Hill},
  year = {2007},
  url = {papers/Fisher2007a.pdf}
}
Fisher, N.W., Baker, T.P. and Baruah, S.K. Algorithms for Determining the Demand--Based Load of a Sporadic Task System 2006 Proceedings of the 12th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 135-146  inproceedings DOI URL 
Abstract: The load parameter of a sporadic task system is defined to be the largest possible cumulative execution requirement that can be generated by jobs of the task system over any time interval, normalized by the length of the interval. This parameter is known to play a very important role in the uniprocessor feasibility analysis of sporadic task systems. In this paper, it is shown that the load of a sporadic task system may be used as an accurate indicator of its feasibility upon preemptive multiprocessors as well. Exact algorithms, and approximate ones that can be guaranteed to be accurate to within an arbitrary additive error > 0, for computing a task system's load are presented and proven correct. The performance of these algorithms is evaluated by simulation over randomly generated task systems.
BibTeX:
@inproceedings{Fisher2006b,
  author = {Fisher, Nathan Wayne and Baker, Theodore P. and Baruah, Sanjoy K.},
  title = {Algorithms for Determining the Demand--Based Load of a Sporadic Task System},
  booktitle = {Proceedings of the 12th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {135--146},
  url = {papers/Fisher2006b.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2006.12}
}
Fisher, N.W. and Baruah, S.K. The Global Feasibility and Schedulability of General Task Models on Multiprocessor Platforms 2007 Proceedings of the 19th Euromicro Conference on Real--Time Systems, pp. 51-60  inproceedings DOI URL 
Abstract: Feasibility analysis determines (prior to system execution--time) whether a specified collection of hard-real-time jobs executed on a processing platform can meet all deadlines. In this paper, we derive near-optimal sufficient tests for determining whether a given collection of jobs can feasibly meet all deadlines upon a specified multiprocessor platform assuming job migration is permitted. These tests are general enough to be applied even when the collection of jobs is incompletely specified. We discuss the applicability of these tests to the scheduling of collections of jobs that are generated by systems of recurrent real-time tasks. We also show that our feasibility conditions may be used to obtain global-EDF schedulability conditions.
BibTeX:
@inproceedings{Fisher2007,
  author = {Fisher, Nathan Wayne and Baruah, Sanjoy K.},
  title = {The Global Feasibility and Schedulability of General Task Models on Multiprocessor Platforms},
  booktitle = {Proceedings of the 19th Euromicro Conference on Real--Time Systems},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {51--60},
  url = {papers/Fisher2007.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2007.34}
}
Fisher, N.W. and Baruah, S.K. Global static--priority scheduling of sporadic task systems on multiprocessor platforms 2006 Proceeding of the IASTED International Conference on Parallel and Distributed Computing and Systems  inproceedings URL 
Abstract: The multiprocessor scheduling of collections of real--time jobs is considered. Sufficient conditions are derived for determining whether a specified system meets all deadlines when scheduled by a static-priority algorithm. These conditions are used to obtain efficient schedulability tests for sporadic task systems scheduled using the popular Deadline-Monotonic real-time scheduling algorithm. Resource-augmentation bounds are provided that quantify the tightness of these schedulability tests.
BibTeX:
@inproceedings{Fisher2006a,
  author = {Fisher, Nathan Wayne and Baruah, Sanjoy K.},
  title = {Global static--priority scheduling of sporadic task systems on multiprocessor platforms},
  booktitle = {Proceeding of the IASTED International Conference on Parallel and Distributed Computing and Systems},
  publisher = {IASTED},
  year = {2006},
  url = {papers/Fisher2006a.pdf}
}
Fisher, N.W. and Baruah, S.K. A Polynomial--Time Approximation Scheme for Feasibility Analysis in Static-Priority Systems with Bounded Relative Deadlines 2005 Proceedings of the 13th International Conference on Real--Time Systems, pp. 14pp  inproceedings URL 
Abstract: Current feasibility tests for the static--priority scheduling of periodic task systems run in pseudo-polynomial time. We present a polynomial-time approximation scheme (PTAS) for feasibility in static-priority systems where each task’s relative deadline is constrained to be at most its period. This test is an approximation with respect to the amount of processor capacity that must be “sacrificed” for the test to become exact. We show that an arbitrary level of accuracy, may be chosen for the approximation scheme, and present a run-time bound that is polynomial in terms of and the number of tasks, n.
BibTeX:
@inproceedings{Fisher2005,
  author = {Fisher, Nathan Wayne and Baruah, Sanjoy K.},
  title = {A Polynomial--Time Approximation Scheme for Feasibility Analysis in Static-Priority Systems with Bounded Relative Deadlines},
  booktitle = {Proceedings of the 13th International Conference on Real--Time Systems},
  year = {2005},
  pages = {14pp},
  url = {papers/Fisher2005.pdf}
}
Fisher, N.W., Baruah, S.K. and Baker, T.P. The Partitioned Scheduling of Sporadic Tasks According to Static--Priorities 2006 Proceedings of the 18th Euromicro Conference on Real--time Systems (ECRTS), pp. 118-127  inproceedings DOI URL 
Abstract: A polynomial--time algorithm is presented for partitioning a collection of sporadic tasks among the processors of an identical multiprocessor platform with static-priority scheduling on each individual processor. Since the partitioning problem is easily seen to be NP-hard in the strong sense, this algorithm is not optimal. A quantitative characterization of its worst-case performance is provided in terms of sufficient conditions and resource augmentation approximation bounds. The partitioning algorithm is also evaluated over randomly generated task systems.
BibTeX:
@inproceedings{Fisher2006,
  author = {Fisher, Nathan Wayne and Baruah, Sanjoy K. and Baker, Theodore P.},
  title = {The Partitioned Scheduling of Sporadic Tasks According to Static--Priorities},
  booktitle = {Proceedings of the 18th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {118--127},
  url = {papers/Fisher2006.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2006.30}
}
Fisher, N.W., Goossens, J. and Baruah, S.K. Optimal Online Multiprocessor Scheduling of Sporadic Real--Time Tasks is Impossible 2010 Real--Time Systems
Vol. 45(1-2), pp. 26-71 
article DOI URL 
Abstract: Optimal online scheduling algorithms are known for sporadic task systems scheduled upon a single processor. Additionally, optimal online scheduling algorithms are also known for restricted subclasses of sporadic task systems upon an identical multiprocessor platform. The research reported in this article addresses the question of existence of optimal online multiprocessor scheduling algorithms for general sporadic task systems. Our main result is a proof of the impossibility of optimal online scheduling for sporadic task systems upon a system comprised of two or more processors. The result is shown by finding a sporadic task system that is feasible on a multiprocessor platform that cannot be correctly scheduled by any possible online, deterministic scheduling algorithm. Since the sporadic task model is a subclass of many more general real--time task models, the nonexistence of optimal scheduling algorithms for the sporadic task systems implies nonexistence for any model which generalizes the sporadic task model.
BibTeX:
@article{Fisher2010,
  author = {Fisher, Nathan Wayne and Goossens, Joël and Baruah, Sanjoy K.},
  title = {Optimal Online Multiprocessor Scheduling of Sporadic Real--Time Tasks is Impossible},
  journal = {Real--Time Systems},
  year = {2010},
  volume = {45},
  number = {1--2},
  pages = {26--71},
  url = {papers/Fisher2010.pdf},
  doi = {http://doi.org/10.1007/s11241--010-9092-7}
}
Frehse, G., Hamann, A., Quinton, S. and Woehrle, M. Formal Analysis of Timing Effects on Closed--Loop Properties of Control Software 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 53-62  inproceedings DOI URL 
Abstract: The theories underlying control engineering and real--time systems engineering use idealized models that mutually abstract from central aspects of the other discipline. Control theory usually assumes jitter-free sampling and negligible (constant) input-output latencies, disregarding complex real-world timing effects. Real-time systems theory uses abstract performance models that neglect the functional behavior and derives worst-case situations with limited expressiveness for control functions, e.g., in physically dominated automotive systems. In this paper, we propose an approach that integrates state-of-the art timing models into functional analysis. We combine physical, control and timing models by representing them as a network of hybrid automata. Closed-loop properties can then be verified on this hybrid automata network by using standard model checkers for hybrid systems. Since the computational complexity is critical for model checking, we discuss abstract models of timing behavior that seem particularly suited for this type of analysis. The approach facilitates systematic co-engineering between both control and real-time disciplines, increasing design efficiency and confidence in the system. The approach is illustrated by analyzing an industrial example, the control software of an electro-mechanical braking system, with the hybrid model checker SpaceEx.
BibTeX:
@inproceedings{Frehse2014,
  author = {Frehse, Goran and Hamann, Arne and Quinton, Sophie and Woehrle, Matthias},
  title = {Formal Analysis of Timing Effects on Closed--Loop Properties of Control Software},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {53--62},
  url = {papers/Frehse2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.28}
}
Fuertes, J.M., Martí, P. and Fohler, G. Jitter compensation for real--time control systems 2001 Proceedings of the 22nd IEEE Real--Time Systems Symposium (RTSS), pp. 39-48  inproceedings DOI URL 
Abstract: In this paper, we first identify the potential violations of control assumptions inherent in standard real--time scheduling approaches (because of the presence of jitters) that causes, degradation in control performance and may even lead to instability. We then develop practical approaches founded on control theory to deal with these violations. Our approach is based on the notion of compensations wherein controller parameters are adjusted at runtime for the presence of jitters. Through time and memory overhead analysis, and by elaborating on the implementation details, we characterize when offline and on-line compensations are feasible. Our experimental results confirm that our approach does compensate for the degraded control performance when EDF and FPS algorithms are used for scheduling the control tasks. Our compensation approach provides us another advantage that leads to better schedulability of control tasks. This derives from the potential to derive more flexible timing constraints, beyond periods and deadlines necessary to apply EDF and FPS. Overall, our approach provides guarantees offline that the control system will be stable at runtime-if temporal requirements are met at runtime-even when actual execution patterns are not known beforehand. With our approach, we can address the problems due to (a) sampling jitters, (b) varying delays between sampling and actuation, or (c) both-not addressable using traditional EDF and FPS based scheduling, or by previous real-time and control integration approaches.
BibTeX:
@inproceedings{Fuertes2001,
  author = {Fuertes, Josep M. and Martí, Pau and Fohler, Gerhard},
  title = {Jitter compensation for real--time control systems},
  booktitle = {Proceedings of the 22nd IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2001},
  pages = {39--48},
  url = {papers/Fuertes2001.pdf},
  doi = {http://doi.org/10.1109/REAL.2001.990594}
}
Funk, S.H. EDF Scheduling on Heterogeneous Multiprocessors 2004 School: University of North Carolina at Chapel Hill  phdthesis URL 
Abstract: The goal of this dissertation is to expand the types of systems available for real--time applications. Specifically, this dissertation introduces tests that ensure jobs will meet their deadlines when scheduled on a uniform heterogeneous multiprocessor using the Earliest Deadline First (EDF) scheduling algorithm, in which jobs with earlier deadlines have higher priority. On uniform heterogeneous multiprocessors, each processor has a speed s, which is the amount of work that processor can complete in one unit of time. Multiprocessor scheduling algorithms can have several variations depending on whether jobs may migrate between processors — i.e., if a job that starts executing on one processor may move to another processor and continue executing. This dissertation considers three different migration strategies: full migration, partitioning, and restricted migration. The full migration strategy applies to all types of job sets. The partitioning and restricted migration strategies apply only to periodic tasks, which generate jobs at regular intervals. In the full migration strategy, jobs may migrate at any time provided a job never executes on two processors simultaneously. In the partitioning strategy, all jobs generated by a periodic task must execute on the same processor. In the restricted migration strategy, different jobs generated by a periodic task may execute on different processors, but each individual job can execute on only one processor. The thesis of this dissertation is Schedulability tests exist for the Earliest Deadline First (EDF) scheduling algorithm on heterogeneous multiprocessors under different migration strategies including full migration, partitioning, and restricted migration. Furthermore, these tests have polynomial-time complexity as a function of the number of processors (m) and the number of periodic tasks (n). • The schedulability test with full migration requires two phases: an O(m) onetime calculation, and an O(n) calculation for each periodic task set. • The schedulability test with restricted migration requires an O(m + n) test for each multiprocessor / task set system. • The schedulability test with partitioning requires two phases: a one-time exponential calculation, and an O(n) calculation for each periodic task set.
BibTeX:
@phdthesis{Funk2004,
  author = {Funk, Shelby Hyatt},
  title = {EDF Scheduling on Heterogeneous Multiprocessors},
  school = {University of North Carolina at Chapel Hill},
  year = {2004},
  url = {papers/Funk2004.pdf}
}
Funk, S.H. and Baruah, S.K. Restricting EDF migration on uniform heterogeneous multiprocessors 2005 TSI. Technique et science informatiques
Vol. 24(8), pp. 917-938 
article URL 
Abstract: Restricted migration of periodic and sporadic tasks on uniform heterogeneous multiprocessors is considered. Migration between different processors of a multiprocessor causes overhead that may be prohibitively high for real--time systems, where accurate timing is essential. Nonetheless, periodic tasks, which generate jobs at regular intervals, may be able to migrate without causing overhead if the migration can be controlled. In particular, if consecutive jobs of the same task do not share any data then they may be allowed to execute on different processors without incurring migration overhead - i.e., restricted migration may be permitted. On uniform multiprocessors, each processor has an associated speed. A job executing on a processor of speed s for t units of time will perform s x t units of work. A utilization-based test for restricted migration on uniform multiprocessors is presented where each processor schedules jobs using the earliest deadline first (EDF) scheduling algorithm.
BibTeX:
@article{Funk2005,
  author = {Funk, Shelby Hyatt and Baruah, Sanjoy K.},
  title = {Restricting EDF migration on uniform heterogeneous multiprocessors},
  journal = {TSI. Technique et science informatiques},
  year = {2005},
  volume = {24},
  number = {8},
  pages = {917--938},
  url = {papers/Funk2005.pdf}
}
Funk, S.H. and Nadadur, V. LRE--TL: An Optimal Multiprocessor Scheduling Algorithm for Sporadic Task Sets 2009 Proceedings of the 17th Real--Time and Network Systems (RTNS), pp. 159-168  inproceedings URL 
Abstract: This paper introduces LRE--TL, a scheduling algorithm based on LLREF, and demonstrates its flexibility and improved running time. Unlike LLREF, LRE-TL is optimal for sporadic task sets. While most LLREF events take O(n) time to run, the corresponding LRE-TL events take O(log n) time. LRE-TL also reduces the number of task preemptions and migrations by a factor of n. Both identical and uniform multiprocessors are considered.
BibTeX:
@inproceedings{Funk2009,
  author = {Funk, Shelby Hyatt and Nadadur, Vijaykant},
  title = {LRE--TL: An Optimal Multiprocessor Scheduling Algorithm for Sporadic Task Sets},
  booktitle = {Proceedings of the 17th Real--Time and Network Systems (RTNS)},
  year = {2009},
  pages = {159--168},
  url = {papers/Funk2009.pdf}
}
Gai, P. Real Time Operating System design for Multiprocessor system--on-a-chip 2004 School: Scuola Superiore Sant'Anna  phdthesis URL 
Abstract: The primary goal for real--time kernel software for single and multiple-processor on a chip is to support the design of timely and cost-effective systems. The kernel must provide time guarantees, in order to predict the timely behavior of the application, an extremely fast response time, in order not to waste computing power other than the application cycles and save as much RAM as possible in order to reduce the overall cost of the chip. The research on real-time software systems has produced algorithms that allow to effectively schedule system resources while guaranteeing the deadlines of the application and to group tasks in a very short number of non-preemptive sets which require much less RAM memory for stack. Unfortunately, up to now, the research focus has been on time guarantees rather than the optimization of memory usage. Furthermore, these techniques do not apply to multiprocessor architectures which are likely to be widely used in future microcontrollers. This thesis presents innovative scheduling and optimization algorithms, which solve the problem of guaranteeing schedulability with an extremely short operating system overhead and minimizing RAM usage. I developed a fast and simple algorithm for sharing resources in homogeneous multiprocessor systems, together with an innovative procedure for assigning a preemption threshold to tasks. When used in conjunction with a preemption threshold assignment algorithm, the algorithm further reduces the RAM usage in multiprocessor systems. Finally, I discuss the problem of multiprocessor scheduling for asymmetric architectures composed by a general purpose CPU and a DSP. The challenging issue addressed in this part is to verify whether the use of a dedicated processor can effectively enhance the performance of an embedded system still maintaining some kind of real-time guarantee. In particular, I provide a method for increasing the schedulability bound both for fixed and dynamic scheduling, allowing a more efcient use of the computational resources.
BibTeX:
@phdthesis{Gai2004,
  author = {Gai, Paolo},
  title = {Real Time Operating System design for Multiprocessor system--on-a-chip},
  school = {Scuola Superiore Sant'Anna},
  year = {2004},
  url = {papers/Gai2004.pdf}
}
Gai, P., Di Natale, M., Lipari, G., Ferrari, A., Gabellini, C. and Marceca, P. A comparison of MPCP and MSRP when sharing resources in the Janus multiple--processor on a chip platform 2003 Proceedings of the 9th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS), pp. 189-198  inproceedings DOI URL 
Abstract: The new generation of embedded systems for automotive applications can take advantage of low--cost multiprocessor system-on a chip architectures. The real-time software applications running on these systems require realtime processor scheduling, and also require the management of the communication and synchronization of tasks executing on different processors with limited blocking time. Conventional real-time technologies, like the Rate Monotonic scheduling algorithm together with the Multiprocessor Priority Ceiling Protocol (MPCP) can be used to this purpose. In earlier work, we proposed the Multiprocessor Stack Resource Policy (MSRP) for scheduling tasks and sharing resources in multiprocessor on a chip architectures. In this paper we present an experimental evaluation that compares the performance of our algorithm with a solution based on Rate Monotonic and MPCP in the con text of the Janus multiple processor architecture. The evaluation of the algorithm has been triggered by our ongoing research in the automotive domain. We report on two sets of experiments: the first addresses a range of generic task configurations to see if one of the algorithms can clearly outperform the other The results show MSRP to be better for random task periods but are probably not conclusive. Later we focus on a more application-specific (also more restrictive) architecture design representing a typical automotive application: a power-train controller In this case, MSRP clearly performs better The performance gap between the two policies can be further increased when considering that MSRP is much simpler to implement, it has a lower overhead, and it allows RAM memory optimization.
BibTeX:
@inproceedings{Gai2003,
  author = {Gai, Paolo and Di Natale, Marco and Lipari, Giuseppe and Ferrari, Alberto and Gabellini, Claudio and Marceca, Paolo},
  title = {A comparison of MPCP and MSRP when sharing resources in the Janus multiple--processor on a chip platform},
  booktitle = {Proceedings of the 9th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS)},
  publisher = {IEEE Computer Society},
  year = {2003},
  pages = {189--198},
  url = {papers/Gai2003.pdf},
  doi = {http://doi.org/10.1109/RTTAS.2003.1203051}
}
Gai, P., Lipari, G. and Di Natale, M. Minimizing memory utilization of real--time task sets in single and multi-processor systems-on-a-chip 2001 Proceedings of the 22nd IEEE Real--Time Systems Symposium (RTSS), pp. 73-83  inproceedings URL 
Abstract: The research on real--time software systems has produced algorithms that allow to effectively schedule system resources while guaranteeing the deadlines of the application and to group tasks in a very short number of non-preemptive sets which require much less RAM memory for stack. Unfortunately, up to now the research focus has been on time guarantees rather than the optimization of RAM usage. Furthermore, these techniques do not apply to multiprocessor architectures which are likely to be widely used in future microcontrollers. This paper presents a fast and simple algorithm for sharing resources in multiprocessor systems, together with an innovative procedure for assigning preemption thresholds to tasks. This allows to guarantee the schedulability of hard real-time task sets while minimizing RAM usage. The experimental part shows the effectiveness of a simulated annealing-based tool that allows to find a near-optimal task allocation. When used in conjunction with our preemption threshold assignment algorithm, our tool further reduces the RAM usage in multiprocessor systems.
BibTeX:
@inproceedings{Gai2001,
  author = {Gai, Paolo and Lipari, Giuseppe and Di Natale, Marco},
  title = {Minimizing memory utilization of real--time task sets in single and multi-processor systems-on-a-chip},
  booktitle = {Proceedings of the 22nd IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2001},
  pages = {73--83},
  url = {papers/Gai2001.pdf}
}
Garey, M.R. and Johnson, D.S. Computers and Intractability: A Guide to the Theory of NP--Completeness 1979   book URL 
BibTeX:
@book{Garey1979,
  author = {Garey, Michael R. and Johnson, David S.},
  title = {Computers and Intractability: A Guide to the Theory of NP--Completeness},
  year = {1979},
  url = {papers/Garey1979.pdf}
}
Garey, M.R. and Johnson, D.S. Two-processor scheduling with start-times and deadlines 1977 SIAM Journal on Computing
Vol. 6, pp. 416-426 
article DOI URL 
Abstract: Given a set T = T_1 ,T_2 , \cdots ,T_n \ of tasks, each T_i having execution time 1, an integer start-time s_i geqq 0 and a deadline d_i > 0, along with precedence constraints among the tasks, we examine the problem of determining whether there exists a schedule on two identical processors that executes each task in the time interval between its start-time and deadline. We present an O(n^3) algorithm that constructs such a schedule whenever one exists. The algorithm may also be used in a binary search mode to find the shortest such schedule or to find a schedule that minimizes maximum “tardiness”. A number of natural extensions of this problem are seen to be NP complete and hence probably intractable.
BibTeX:
@article{Garey1977,
  author = {Garey, Michael R. and Johnson, David S.},
  title = {Two-processor scheduling with start-times and deadlines},
  journal = {SIAM Journal on Computing},
  year = {1977},
  volume = {6},
  pages = {416--426},
  url = {papers/Garey1977.pdf},
  doi = {http://doi.org/10.1137/0206029}
}
Garside, J. and Audsley, N.C. WCET Preserving Hardware Prefetch for Many--Core Real-Time Systems 2014 Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS), pp. 193-202  inproceedings DOI URL 
Abstract: There is an obvious bus bottleneck when multiple CPUs within a Many--Core architecture share the same physical off-chip memory (eg. DDR / DRAM). Worst-Case Execution Time (WCET) analysis of application tasks will inevitably include the effects of sharing the memory bus amongst CPUs; likewise average case execution times will include effects of individual memory accesses being slowed by interference with other memory requests from other CPUs. One approach for mitigating this is to use a hardware prefetch to move instructions and data from memory to the CPU cache before a cache miss instigates a memory request. However, in a real-time system, there is a trade-off between issuing prefetch requests to off-chip memory and hence reducing bandwidth available to serving CPU cache misses; and the gain in the fact that some CPU cache misses are avoided by the prefetch with the memory system seeing reduced memory requests.

In this paper we propose, analyse and show the implementation of a hardware prefetcher designed so that WCET of application tasks are not affected by the run--time behaviour of the prefetcher, i.e. it utilises spare time within the memory system to issue prefetch requests and forward them to the appropriate CPU. As well as not affecting WCET times, the prefetcher enables significant reduction in average case execution times of application tasks, showing the efficacy of the approach.

BibTeX:
@inproceedings{Garside2014,
  author = {Garside, Jamie and Audsley, Neil C.},
  title = {WCET Preserving Hardware Prefetch for Many--Core Real-Time Systems},
  booktitle = {Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS)},
  publisher = {ACM Press},
  year = {2014},
  pages = {193--202},
  url = {papers/Garside2014.pdf},
  doi = {http://doi.org/10.1145/2659787.2659824}
}
George, L. Etat de l’art sur la robustesse temporelle des systèmes temps--réel monoprocesseur 2008 Journal Européen des Systèmes Automatisés
Vol. 42(9), pp. 1135-1160 
article URL 
Abstract: Nous proposons dans cet article un état de l’art sur la robustesse temporelle des systèmes temps--réel. Nous considérons les ordonnancements monoprocesseurs préemptifs à priorités fixes (FP: Fixed Priority scheduling) et à priorités dynamiques Earliest Deadline First (EDF). Le modèle de tâche est le modèle périodique où une tâche est définie par sa durée d’exécution pire cas (WCET), sa période et son échéance de terminaison au plus tard. Nous étudions les analyses de sensibilité caractérisant les déviations limites acceptable des WCET, périodes ou échéances garantissant l’ordonnançabilité des tâches. Nous étudions ensuite les solutions algorithmiques utilisables en ligne dans un système temps-réel pour garantir sa robustesse temporelle.
BibTeX:
@article{George2008,
  author = {George, Laurent},
  title = {Etat de l’art sur la robustesse temporelle des systèmes temps--réel monoprocesseur},
  journal = {Journal Européen des Systèmes Automatisés},
  year = {2008},
  volume = {42},
  number = {9},
  pages = {1135--1160},
  url = {papers/George2008.pdf}
}
George, L., Courbin, P. and Sorel, Y. Job vs. portioned partitioning for the earliest deadline first semi--partitioned scheduling 2011 Journal of Systems Architecture
Vol. 57(5), pp. 518-535 
article DOI URL 
Abstract: In this paper, we focus on the semi--partitioned scheduling of sporadic tasks with constrained deadlines and identical processors. We study two cases of semi-partitioning: (i) the case where the worst case execution time (WCET) of a job can be portioned, each portion being executed on a dedicated processor, according to a static pattern of migration; (ii) the case where the jobs of a task are released on a processor, 1 time out of p, where p is an integer at most equal to the number of processors, according to a round-robin migration pattern. The first approach has been investigated in the state-of-the-art by migrating a job at its local deadline, computed from the deadline of the task it belongs to. We study several local deadline assignment heuristics (fair, based on processor utilization and based on the minimum acceptable local deadline for a job on a processor). In both cases, we propose feasibility conditions for the schedulability of sporadic tasks scheduled using earliest deadline first (EDF) semi-partitioned scheduling. We show that the load function used for global scheduling to establish the feasibility of sporadic task sets exhibits interesting properties in the semi-partitioning context. We carry out simulations to study the performance of the two approaches in terms of success rate and number of migrations, for platforms composed of four and eight processors. We compare the performance of these semi-partitioned heuristics with the performance of classical partitioned scheduling algorithms and with a global scheduling heuristic which is currently considered to have good performances.
BibTeX:
@article{George2011,
  author = {George, Laurent and Courbin, Pierre and Sorel, Yves},
  title = {Job vs. portioned partitioning for the earliest deadline first semi--partitioned scheduling},
  journal = {Journal of Systems Architecture},
  year = {2011},
  volume = {57},
  number = {5},
  pages = {518--535},
  url = {papers/George2011.pdf},
  doi = {http://doi.org/10.1016/j.sysarc.2011.02.008}
}
George, L., Rivierre, N. and Spuri, M. Preemptive and Non--Preemptive Real-Time UniProcessor Scheduling 1996 (RR-2966)School: INRIA  techreport URL 
Abstract: Scheduling theory, as it applies to hard--real-time environment, has been widely studied in the last twenty years and it might be unclear to make it out within the plethora of results available. Our goal is first to collect in a single paper the results known for uniproces sor, non-idling, preemptive/non-preemptive, fixed/dynamic priority driven contexts, consid ering general task sets as a central figure for the description of possible processor loads. Second to establish new results when needed. In particular, optimality, feasibility conditions and worst-case response times are examined largely by utilizing the concepts of workload, processor demand and busy period. Some classic extensions such as jitter, resource sharing are also considered. Although this work is not oriented toward a formal comparison of these results, it appears that preemptive and non-preemptive scheduling are closely related and that the analysis of fixed versus dynamic scheduling might be unified according to the concept of higher priority busy period. In particular, we introduce the notion of deadline-d busy period for EDF sched ules, that we conjecture to be an interesting parallel of the level-i busy period, a concept already used in the analysis of fixed priority driven scheduling.
BibTeX:
@techreport{George1996,
  author = {George, Laurent and Rivierre, Nicolas and Spuri, Marco},
  title = {Preemptive and Non--Preemptive Real-Time UniProcessor Scheduling},
  school = {INRIA},
  year = {1996},
  number = {RR--2966},
  url = {papers/George1996.pdf}
}
Goodenough, J.B. and Sha, L. The Priority Ceiling Protocol: A Method for Minimizing the Blocking of High--Priority Ada Tasks 1988 (CMU/SEI-88-SR-4)School: Carnegie Mellon University  techreport URL 
Abstract: he priority ceiling protocol is a new technique that addresses the priority inversion problem, i.e., the possibility that a high--priority task can be delayed by a low-priroity task. Under the priority ceiling protocol, a high priority task can be blocked at most once by a lower proirity task. This paper defines how to apply the protocol to Ada. In particular, restrictions on the use of task priorities in Ada are defined as well as restrictions on the use of Ada tasking constructs. An extensive example illustrating the behavior guaranteed by the protocol is given.
BibTeX:
@techreport{Goodenough1988,
  author = {Goodenough, John B. and Sha, Lui},
  title = {The Priority Ceiling Protocol: A Method for Minimizing the Blocking of High--Priority Ada Tasks},
  school = {Carnegie Mellon University},
  year = {1988},
  number = {CMU/SEI--88-SR-4},
  url = {papers/Goodenough1988.pdf}
}
Goossens, J. Scheduling of Offset Free Systems 2003 Real--Time Systems
Vol. 24(2), pp. 239-258 
article DOI URL 
Abstract: In this paper, we study the problem of scheduling hard real--time periodic tasks. We consider independant tasks which are characterized by a period, a hard deadline and a computation time, but where the offsets may be chosen by the scheduling algorithm. We first show that we can restrict the problem by considering non-equivalent offset assignments. More precisely, we show that there are finitely many non-equivalent offset assignments and we propose to reduce significantly this number and consider only the minimal number of non-equivalent offset assignments. However the number of combinations remains exponential; for this reason, we also propose a nearly optimal algorithm with a more reasonable time complexity.
BibTeX:
@article{Goossens2003a,
  author = {Goossens, Joël},
  title = {Scheduling of Offset Free Systems},
  journal = {Real--Time Systems},
  year = {2003},
  volume = {24},
  number = {2},
  pages = {239--258},
  url = {papers/Goossens2003a.pdf},
  doi = {http://doi.org/10.1023/A:1021782503695}
}
Goossens, J. Scheduling of Hard Real--Time Periodic Systems with Various Kinds of Deadline and Offset Constraints 1999 School: Université Libre de Bruxelles  phdthesis URL 
BibTeX:
@phdthesis{Goossens1999,
  author = {Goossens, Joël},
  title = {Scheduling of Hard Real--Time Periodic Systems with Various Kinds of Deadline and Offset Constraints},
  school = {Université Libre de Bruxelles},
  year = {1999},
  url = {papers/Goossens1999.pdf}
}
Goossens, J. and Berten, V. Gang FTP scheduling of periodic and parallel rigid real--time tasks 2010 Proceedings of the 18th Real--Time and Network Systems (RTNS), pp. 189-196  inproceedings URL 
Abstract: In this paper we consider the scheduling of periodic and parallel rigid tasks. We provide (and prove correct) an exact schedulability test for Fixed Task Priority (FTP) Gang scheduler sub--classes: Parallelism Monotonic, Idling, Limited Gang, and Limited Slack Reclaiming. Additionally, we study the predictability of our schedulers: we show that Gang FJP schedulers are not predictable and we identify several sub-classes which are actually predictable. Moreover, we extend the definition of rigid, moldable and malleable jobs to recurrent tasks.
BibTeX:
@inproceedings{Goossens2010,
  author = {Goossens, Joël and Berten, Vandy},
  title = {Gang FTP scheduling of periodic and parallel rigid real--time tasks},
  booktitle = {Proceedings of the 18th Real--Time and Network Systems (RTNS)},
  publisher = {IRIT Press},
  year = {2010},
  pages = {189--196},
  url = {papers/Goossens2010.pdf}
}
Goossens, J. and Devillers, R. The Non--Optimality of the Monotonic Priority Assignments for Hard Real-Time Offset Free Systems 1997 Real--Time Systems
Vol. 13(2), pp. 107-126 
article URL 
Abstract: In this paper, we study the problem of scheduling hard real--time periodic tasks with static priority pre-emptive algorithms. We consider tasks which are characterized by a period, a hard deadline, a computation time and an offset (the time of the first request), where the offsets may be chosen by the scheduling algorithm, hence the denomination offset free systems. We study the rate monotonic and the deadline monotonic priority assignments for this kind of system and we compare the offset free systems and the asynchronous systems in terms of priority assignment. Hence, we show that the rate and the deadline monotonic priority assignments are not optimal for offset free systems.
BibTeX:
@article{Goossens1997,
  author = {Goossens, Joël and Devillers, Raymond},
  title = {The Non--Optimality of the Monotonic Priority Assignments for Hard Real-Time Offset Free Systems},
  journal = {Real--Time Systems},
  year = {1997},
  volume = {13},
  number = {2},
  pages = {107--126},
  url = {papers/Goossens1997.pdf}
}
Goossens, J., Devillers, R. and Funk, S.H. Tie--breaking for EDF on multiprocessor platforms 2002 Proceeding of the Work--in-Progress Session of the 23rd IEEE Real-Time System Symposium (WiP RTSS), pp. 17-20  inproceedings URL 
Abstract: Scheduling real--time systems on multiprocessors introduces complexities that do not arise when using uniprocessors. When scheduling using EDF on multiprocessor platforms, breaking deadline ties in different ways can change the resulting schedule dramatically. We consider methods to resolve the ambiguities in EDF priorities due to coincident deadlines. We show that no optimal ambiguity solver can be online. We also show that no optimal static tiebreaker exists even if we relax the on-line property.
BibTeX:
@inproceedings{Goossens2002,
  author = {Goossens, Joël and Devillers, Raymond and Funk, Shelby Hyatt},
  title = {Tie--breaking for EDF on multiprocessor platforms},
  booktitle = {Proceeding of the Work--in-Progress Session of the 23rd IEEE Real-Time System Symposium (WiP RTSS)},
  year = {2002},
  pages = {17--20},
  url = {papers/Goossens2002.pdf}
}
Goossens, J., Funk, S.H. and Baruah, S.K. Priority--Driven Scheduling of Periodic Task Systems on Multiprocessors 2003 Real--Time Systems
Vol. 25(2-3), pp. 187-205 
article URL 
Abstract: The scheduling of systems of periodic tasks upon multiprocessor platforms is considered. Utilization--based conditions are derived for determining whether a periodic task system meets all deadlines when scheduled using the earliest deadline first scheduling algorithm (EDF) upon a given multiprocessor platform. A new priority-driven algorithm is proposed for scheduling periodic task systems upon multiprocessor platforms: this algorithm is shown to successfully schedule some task systems for which EDF may fail to meet all deadlines.
BibTeX:
@article{Goossens2003,
  author = {Goossens, Joël and Funk, Shelby Hyatt and Baruah, Sanjoy K.},
  title = {Priority--Driven Scheduling of Periodic Task Systems on Multiprocessors},
  journal = {Real--Time Systems},
  year = {2003},
  volume = {25},
  number = {2--3},
  pages = {187--205},
  url = {papers/Goossens2003.pdf}
}
Goossens, J. and Macq, C. Limitation of the Hyper--Period in Real-Time Periodic Task Set Generation 2001 Proceedings of the 9th International Conference on Real--Time Systems (RTS), pp. 133-148  inproceedings URL 
Abstract: This paper presents a method used in order to generate arbitrary task systems, compound of periodic and independent tasks. The originality of this methods relays on a judicious choice of the periods of the tasks in order to reduce the lcm of the periods (and the simulation duration required in order to study such a system). The authors prove that the lcm of n integers might be very high: they propose an upper bound of the lcm of n integers, given by e m where m is the least prime number greater than the greatest integer in the set of the n integers. Then, they present a method in order to choose the periods of the tasks which imply a bounded lcm of the periods. The method relies on the decomposition of an integer in distinct prime factors. A second algorithm is proposed in order to obtain the other temporal parameters of the task system to generate. Then, an example is given in order to illustrate the method: several task systems are generated for performance analysis of classical scheduling algorithms, in term of preemption.
BibTeX:
@inproceedings{Goossens2001,
  author = {Goossens, Joël and Macq, Christophe},
  title = {Limitation of the Hyper--Period in Real-Time Periodic Task Set Generation},
  booktitle = {Proceedings of the 9th International Conference on Real--Time Systems (RTS)},
  year = {2001},
  pages = {133--148},
  url = {papers/Goossens2001.pdf}
}
Goossens, J., Richard, P., Lindström, M. and Lupu, I.I. Job Partitioning Strategies for Multiprocessor Scheduling of Real--Time Periodic Tasks with Restricted Migrations 2012 Proceedings of the 20th International Conference on Real--Time and Network Systems (RTNS), pp. 141-150  inproceedings DOI URL 
Abstract: In this work, we consider the scheduling of real--time periodic tasks on multiprocessors under a restricted-migration constraint (tasks are allowed to migrate whereas jobs are not). We first propose a technique, (offline) job partitioning, which statically assigns jobs to processors before execution. We show that (offline) job partitioning strictly dominates both partitioned and restricted-migration scheduling. We then consider r-RM, a restricted-migration variant of global RM, we design a sufficient schedulability test and we provide a speedup factor for the scheduler.
BibTeX:
@inproceedings{Goossens2012,
  author = {Goossens, Joël and Richard, Pascal and Lindström, Markus and Lupu, Irina Iulia},
  title = {Job Partitioning Strategies for Multiprocessor Scheduling of Real--Time Periodic Tasks with Restricted Migrations},
  booktitle = {Proceedings of the 20th International Conference on Real--Time and Network Systems (RTNS)},
  publisher = {ACM},
  year = {2012},
  pages = {141--150},
  url = {papers/Goossens2012.pdf},
  doi = {http://doi.org/10.1145/2392987.2393005}
}
Goswami, D., Lukasiewycz, M., Schneider, R. and Chakraborty, S. Time--triggered implementations of mixed-criticality automotive software 2012 Proceedings of the Conference on Design, Automation and Test in Europe (DATE), pp. 1227-1232  inproceedings DOI URL 
Abstract: We present an automatic schedule synthesis framework for applications that are mapped onto distributed time--triggered automotive platforms where multiple Electronic Control Units (ECUs) are synchronized over a FlexRay bus. We classify applications into two categories (i) safety-critical control applications with stability and performance constraints, and (ii) time-critical applications with only deadline constraints. Our proposed framework can handle such mixed constraints arising from timing, control stability, and performance requirements. In particular, we synthesize schedules that optimize control performance and respects the timing requirements of the real-time applications. An Integer Linear Programming (ILP) problem is formulated by modeling the ECU and bus schedules as a set of constraints for optimizing both linear or quadratic control performance functions.
BibTeX:
@inproceedings{Goswami2012,
  author = {Goswami, Dip and Lukasiewycz, Martin and Schneider, Reinhard and Chakraborty, Samarjit},
  title = {Time--triggered implementations of mixed-criticality automotive software},
  booktitle = {Proceedings of the Conference on Design, Automation and Test in Europe (DATE)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {1227--1232},
  url = {papers/Goswami2012.pdf},
  doi = {http://doi.org/10.1109/DATE.2012.6176680}
}
Goubier, T., Sirdey, R., Louise, S. and David, V. ΣC: A Programming Model and Language for Embedded Manycores 2011
Vol. 7016Proceedings of the 11th International Conference on Algorithms and Architectures for Parallel Processing (ICA3PP), pp. 385-394 
inproceedings DOI URL 
Abstract: We present ΣC, a programming model and language for high performance embedded manycores. The programming model is based on process networks with non determinism extensions and process behavior specifications. The language itself extends C, with parallelism, composition and process abstractions. It is intended to support architecture independent, high--level parallel programming on embedded manycores, and allows for both low execution overhead and strong execution guarantees. ΣC is being developed as part of an industry-grade tool chain for a high performance embedded manycore architecture.
BibTeX:
@inproceedings{Goubier2011,
  author = {Goubier, Thierry and Sirdey, Renaud and Louise, Stéphane and David, Vincent},
  title = {ΣC: A Programming Model and Language for Embedded Manycores},
  booktitle = {Proceedings of the 11th International Conference on Algorithms and Architectures for Parallel Processing (ICA3PP)},
  publisher = {Springer},
  year = {2011},
  volume = {7016},
  pages = {385--394},
  url = {papers/Goubier2011.pdf},
  doi = {http://doi.org/10.1007/978--3-642-24650-0_33}
}
Grieu, J. Analyse et évaluation de techniques de commutation Ethernet pour l’interconnexion des systèmes avioniques 2004 School: Institut National Polytechnique de Toulouse  phdthesis URL 
Abstract: L’augmentation du nombre et de la complexité des fonctions embarquées dans les aéronefs actuels implique un accroissement très important de la quantité de données échangées. Les architectures avioniques existantes reposent sur des bus avioniques de conception assez ancienne. Parmi ceux--ci, on peut citer le bus ARINC 429, bus mono émetteur très répandu, fiable et d’une grande simplicité d’utilisation mais aux performances limitées (débit maximal de 100 kbits/s). De plus l’accroissement des fonctions, et leur distribution sur plusieurs équipements, s’accompagnent non seulement d’une augmentation du volume total de données échangées, mais aussi d’une augmentation du nombre d’interconnexions nécessaires : les échanges ne suivent plus un simple schéma producteur – consommateur, mais ont lieu entre de nombreux intervenants. Il est évident dans un tel contexte que les bus mono émetteurs brident la croissance du système avionique. Pour répondre à cette augmentation des interconnexions, Boeing a choisi d’embarquer dans le cockpit du 777 des bus ARINC 629, bus multi émetteurs autorisant de bien meilleures performances (2 Mbps, jusqu’à 120 utilisateurs). Il apparaît cependant que cette amélioration de bus avionique implique des coûts de développement de composants spécifiques très importants. Ces différents facteurs font que la technologie des bus avioniques n’est plus comme il y a quelques années considérée comme une solution satisfaisante au problème de l’évolution du trafic dans les réseaux avioniques civils. La solution retenue par Airbus pour l’A380 repose sur la technologie de l’Ethernet commuté. Le principal avantage de l’utilisation d’Ethernet est qu’il s’agit d’un standard bien connu, ce qui permet une réutilisation d’outils de développement ainsi que de composants matériels existants (COTS : commercial off-the-shelf). De plus, il existe une longue expérience
industrielle de ce standard, ce qui permet d’avoir une bonne confiance en la fiabilité du matériel et sur la facilité de sa maintenance. L’inconvénient majeur de l’Ethernet, vis--à-vis d’une application dans des systèmes avioniques, est le non-déterminisme intrinsèque de sa méthode d’accès au support physique, CSMA/CD. La solution Ethernet commuté Full Duplex retenue permet de contourner cet inconvénient. Dans cette architecture, chaque équipement est seulement relié à un commutateur, par le biais d’un câble Full Duplex. De cette manière, il ne peut plus y avoir de collision sur le support physique, et le CSMA/CD n’est plus nécessaire. L’interconnexion des éléments repose donc sur de s commutateurs Ethernet, reliés entre eux par la même technologie. Une réflexion importante a été mise en place, autour du projet de norme ARINC 664, quant aux adaptations qu’il est nécessaire d’effectuer pour utiliser cette architecture dans le contexte aéronautique, et pouvoir ainsi profiter d’une technologie bien plus performante que les bus avioniques classiques (100 Mbps), tout en utilisant des composants existants. Le projet de norme prescrit en premier lieu de contrôler les flux avant leur entrée dans le réseau, grâce à la notion de Virtual Link. D’autre part, il spécifie que des commutateurs compatibles avec la norme 802.1D, dans leur version avionable, devront être utilisés.
BibTeX:
@phdthesis{Grieu2004,
  author = {Grieu, Jérôme},
  title = {Analyse et évaluation de techniques de commutation Ethernet pour l’interconnexion des systèmes avioniques},
  school = {Institut National Polytechnique de Toulouse},
  year = {2004},
  url = {papers/Grieu2004.pdf}
}
Griffin, D., Lesage, B., Burns, A. and Davis, R.I. Lossy Compression for Worst--Case Execution Time Analysis of PLRU Caches 2014 Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS), pp. 203-212  inproceedings DOI URL 
Abstract: This paper outlines how Lossy Compression, a branch of Information Theory relating to the compact representation of data while retaining important information, can be applied to the Worst Case Execution Time analysis problem. In particular, we show that by applying lossy compression to the data structures involved in the collecting semantics of a given component, for example a PLRU cache, a useful analysis can be derived. While such an analysis could be found via other means, the application of Lossy Compression provides a formal method and eases the process of discovering the analysis. Further, as the compression and its application are formally specified, such an analysis can be made correct--by-construction rather than relying on an after-the-fact proof.
BibTeX:
@inproceedings{Griffin2014,
  author = {Griffin, David and Lesage, Benjamin and Burns, Alan and Davis, Robert Ian},
  title = {Lossy Compression for Worst--Case Execution Time Analysis of PLRU Caches},
  booktitle = {Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS)},
  publisher = {ACM Press},
  year = {2014},
  pages = {203--212},
  url = {papers/Griffin2014.pdf},
  doi = {http://doi.org/10.1145/2659787.2659807}
}
Guan, N., Gu, C., Stigge, M., Deng, Q. and Yi, W. Approximate Response Time Analysis of Real--Time Task Graphs 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 304-313  inproceedings DOI URL 
Abstract: The response time analysis problem is intractable for most existing real--time task models, except the simplest ones. Exact solutions for this problem in general have exponential complexity, and may run into scalability problems for large-scale task systems. In this paper, we study approximate analysis for static-priority scheduling of the Digraph Real-Time task model, which is a generalization of most existing graph-based real-time task models. We present two approximate analysis methods RBF and IBF, both of which have pseudo-polynomial complexity. We quantitatively evaluate their analysis precision using the metric speedup factor. We prove that RBF has a speedup factor of 2, and this is tight even for dual-task systems. The speedup factor of IBF is an increasing function with respect to k, the number of interfering tasks. This function converges to 2 as k approaches infinity and equals 1 when k = 1, implying that the IBF analysis is exact for dual-task systems. We also conduct simulation experiments to evaluate the precision and efficiency of RBF and IBF with randomly generated task sets. Results show that the proposed approximate analysis methods have very high efficiency with low precision loss.
BibTeX:
@inproceedings{Guan2014,
  author = {Guan, Nan and Gu, Chuancai and Stigge, Martin and Deng, Qingxu and Yi, Wang},
  title = {Approximate Response Time Analysis of Real--Time Task Graphs},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {304--313},
  url = {papers/Guan2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.20}
}
Guan, N., Stigge, M., Yi, W. and Yu, G. Fixed--Priority Multiprocessor Scheduling with Liu & Layland’s Utilization Bound 2010 Proceedings of the 16th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS), pp. 165-174  inproceedings DOI URL 
Abstract: Liu and Layland discovered the famous utilization bound N(2^1N--1) for fixed-priority scheduling on singleprocessor systems in the 1970’s. Since then, it has been a long standing open problem to find fixed-priority scheduling algorithms with the same bound for multiprocessor systems. In this paper, we present a partitioning-based fixed-priority multiprocessor scheduling algorithm with Liu and Layland’s utilization bound.
BibTeX:
@inproceedings{Guan2010,
  author = {Guan, Nan and Stigge, Martin and Yi, Wang and Yu, Ge},
  title = {Fixed--Priority Multiprocessor Scheduling with Liu & Layland’s Utilization Bound},
  booktitle = {Proceedings of the 16th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {165--174},
  url = {papers/Guan2010.pdf},
  doi = {http://doi.org/10.1109/RTAS.2010.39}
}
Guan, N., Stigge, M., Yi, W. and Yu, G. New Response Time Bounds for Fixed Priority Multiprocessor Scheduling 2009 Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS), pp. 387-397  inproceedings DOI URL 
Abstract: Recently, there have been several promising techniques developed for schedulability analysis and response time analysis for multiprocessor systems based on over--approximation. This paper contains two contributions. First, to improve the analysis precision, we apply Baruah’s window analysis framework [6] to response time analysis for sporadic tasks on multiprocessor systems where the deadlines of tasks are within their periods. The crucial observation is that for global fixed priority scheduling, a response time bound of each task can be efficiently estimated by fixed-point computation without enumerating all the busy window sizes as in [6] for schedulability analysis. The technique is proven to dominate theoretically state-of-the-art techniques for response time analysis for multiprocessor systems. Our experiments also show that the technique results in significant performance improvement compared with several existing techniques for multiprocessor schedulability analysis. As the second main contribution of this paper, we extend the proposed technique to task systems with arbitrary deadlines, allowing tasks to have deadlines beyond the end of their periods. This is a non-trivial extension even for single-processor systems. To our best knowledge, this is the first work of response time analysis for multiprocessor systems in this setting, which involves sophisticated techniques for the characterization and computation of response time bounds.
BibTeX:
@inproceedings{Guan2009,
  author = {Guan, Nan and Stigge, Martin and Yi, Wang and Yu, Ge},
  title = {New Response Time Bounds for Fixed Priority Multiprocessor Scheduling},
  booktitle = {Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {387--397},
  url = {papers/Nuan2009.pdf},
  doi = {http://doi.org/10.1109/RTSS.2009.11}
}
Guo, Z., Liu, R., Xu, X. and Yan, K. A Survey of Real-Time Automotive Systems 2015 School: University of North Carolina at Chapel Hill  techreport URL 
BibTeX:
@techreport{Guo2015,
  author = {Guo, Zhishan and Liu, Rui and Xu, Xinghao and Yan, Kecheng},
  title = {A Survey of Real-Time Automotive Systems},
  school = {University of North Carolina at Chapel Hill},
  year = {2015},
  url = {papers/Guo2015.pdf}
}
Gutiérrez, J.J., Palencia, J.C. and González Harbour, M. Holistic schedulability analysis for multipacket messages in AFDX networks 2014
Vol. 50(2)Real--Time Systems, pp. 230-269 
inproceedings DOI  
Abstract: The ARINC--664, Part 7 (AFDX) standard defines a communication network based on Ethernet and the UDP/IP protocols. Contrary to general-purpose Ethernet, the timing behavior in AFDX is deterministic due to the use of special network switches and end systems with static routing tables and traffic policing at the sending end through mechanisms called virtual links. Even though the latencies in this network are bounded, there are scheduling and contention effects that need to be analyzed. In this paper we develop a response-time analysis for multipacket messages transmitted through an AFDX network including the scheduling of the virtual links and sub-virtual links, and also the contention in the end systems and in the switches. This analysis allows us to obtain worst-case latencies and output jitter for the network messages with a precise modeling of the sending and receiving ends. These results can be integrated in a holistic approach with the response time analysis of the threads in the processing nodes to obtain end-to-end response times in heterogeneous distributed systems.
BibTeX:
@inproceedings{Gutierrez2014,
  author = {Gutiérrez, J. Javier and Palencia, J. Carlos and González Harbour, Michael},
  title = {Holistic schedulability analysis for multipacket messages in AFDX networks},
  booktitle = {Real--Time Systems},
  publisher = {Springer},
  year = {2014},
  volume = {50},
  number = {2},
  pages = {230--269},
  doi = {http://doi.org/10.1007/s11241--013-9192-2}
}
Ha, R. Validating timing constraints in multiprocessor and distributed real--time systems 1995 School: University of Illinois, Dept. of Computer Science  phdthesis  
BibTeX:
@phdthesis{Ha1995,
  author = {Ha, Rhan},
  title = {Validating timing constraints in multiprocessor and distributed real--time systems},
  school = {University of Illinois, Dept. of Computer Science},
  year = {1995}
}
Ha, R. and Liu, J.W.S. Validating timing constraints in multiprocessor and distributed real--time systems 1994 Proceedings of the 14th International Conference on Distributed Computing Systems (ICDCS), pp. 162-171  inproceedings DOI URL 
Abstract: In multiprocessor and distributed real--time systems, scheduling jobs dynamically on processors is likely to achieve better performance. However, analytical and efficient validation methods to determine whether all the timing constraints are met do not exist for systems using modern dynamic scheduling strategies, and exhaustive simulation and testing are unreliable and expensive. This paper describes several worst-case bounds and efficient algorithms for validating systems in which jobs have arbitrary timing constraints and variable execution times and are scheduled on processors dynamically in a priority-driven manner. The special cases of the validation problem considered here are concerned with independent jobs that are (1) preemptable and migratable, or (2) preemptable and nonmigratable, or (3) nonpreemptable.
BibTeX:
@inproceedings{Ha1994,
  author = {Ha, Rhan and Liu, Jane W. S.},
  title = {Validating timing constraints in multiprocessor and distributed real--time systems},
  booktitle = {Proceedings of the 14th International Conference on Distributed Computing Systems (ICDCS)},
  publisher = {IEEE Computer Society},
  year = {1994},
  pages = {162--171},
  url = {papers/Ha1994.pdf},
  doi = {http://doi.org/10.1109/ICDCS.1994.302407}
}
Hamann, A., Racu, R. and Ernst, R. Multi--Dimensional Robustness Optimization in Heterogeneous Distributed Embedded Systems 2007 Proceedings of the 13th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS), pp. 269-280  inproceedings URL 
Abstract: Embedded system optimization typically considers objectives such as cost, timing, buffer sizes, and power consumption. Robustness criteria, i.e. sensitivity of the system to property variations like execution and transmission delays, input data rates, CPU clock rates, etc., has found less attention despite its practical relevance. In this paper we present an approach for optimizing multidimensional robustness criteria in complex distributed embedded systems. The key novelty of our approach is a scalable stochastic multi--dimensional sensitivity analysis technique approximating the sought-after sensitivity front from two sides, i.e. coming from the space of working and from the space of non-working system property combinations. We utilize the proposed stochastic sensitivity analysis to derive multi-dimensional robustness metrics, which are capable of bounding the robustness of given system configurations with little computational effort. The proposed metrics can significantly speed up multidimensional robustness optimization by quickly identifying promising system configurations, whose in-depth robustness evaluation can be performed subsequently to the optimization process.
BibTeX:
@inproceedings{Hamann2007,
  author = {Hamann, Arne and Racu, Razvan and Ernst, Rolf},
  title = {Multi--Dimensional Robustness Optimization in Heterogeneous Distributed Embedded Systems},
  booktitle = {Proceedings of the 13th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS)},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {269--280},
  url = {papers/Hamman2007.pdf}
}
Han, S. and Park, M. Predictability of Least Laxity First Scheduling Algorithm on Multiprocessor Real--Time Systems 2006 Emerging Directions in Embedded and Ubiquitous Computing
Vol. 4097, pp. 755-764 
article DOI URL 
Abstract: A priority--driven scheduling algorithm is said to be start time (finish time) predictable if the start time (finish time) of jobs in the schedule where each job executes for its actual execution time is bounded by the start times (finish times) of jobs in the schedules where each job executes for its maximum/minimum execution time. In this paper, we study the predictability of a job-level dynamic priority algorithm, LLF (Least Laxity First), on multiprocessor real-time systems. We present a necessary and sufficient condition for a priority-driven algorithm to be start time (finish time) predictable. Then, in LLF scheduling, we show that both the start time and the finish time are predictable if the actual execution times cannot be known. However, solely the finish time is predictable if the actual execution times can be known.
BibTeX:
@article{Han2006,
  author = {Han, Sangchul and Park, Minkyu},
  title = {Predictability of Least Laxity First Scheduling Algorithm on Multiprocessor Real--Time Systems},
  journal = {Emerging Directions in Embedded and Ubiquitous Computing},
  year = {2006},
  volume = {4097},
  pages = {755--764},
  url = {Han2006.pdf},
  doi = {http://doi.org/10.1007/11807964_76}
}
Harbour, M.G., Klein, M.H. and Lehoczky, J.P. Timing Analysis for Fixed--Priority Scheduling of Hard Real-Time Systems 1994 IEEE Transactions on Software Engineering
Vol. 20(1), pp. 13-28 
article DOI URL 
Abstract: This paper presents a timing analysis for a quite general hard real--time periodic task set on a uniprocessor using fixed-priority methods. Periodic tasks are composed of serially executed subtasks, where each subtask is characterized by an execution time, a fixed priority, and a deadline. A method for determining the schedulability of each task and subtask is presented along with its theoretical underpinnings. This method can be used to analyze the schedulability of any task set on a uniprocessor whose priority structure can be modeled as serially executed subtasks, which can lead to a very complex priority structure. Important examples include task sets that involve interrupts, certain synchronization protocols, certain precedence constraints, nonpreemptible sections, and some message-passing systems. The method is illustrated by a robotics example.
BibTeX:
@article{Harbour1994,
  author = {Harbour, Michael Gonzalez and Klein, Mark H. and Lehoczky, John P.},
  title = {Timing Analysis for Fixed--Priority Scheduling of Hard Real-Time Systems},
  journal = {IEEE Transactions on Software Engineering},
  year = {1994},
  volume = {20},
  number = {1},
  pages = {13--28},
  url = {papers/Harbour1994.pdf},
  doi = {http://doi.org/10.1109/32.263752}
}
Harbour, M.G., Klein, M.H. and Lehoczky, J.P. Fixed priority scheduling periodic tasks with varying execution priority 1991 Proceedings of the 12th IEEE Real--Time Systems Symposium (RTSS), pp. 116-128  inproceedings DOI URL 
Abstract: This paper considers the problem of fixed priority scheduling of periodic tasks where each task’s execution priority may vary. Periodic tasks are decomposed into serially executed subtasks. where each subtask is characterized by an execution time and a fixed priority, and is permitted to have a deadline. A method for determining the schedulability of each task is presented along with its theoretical underpinnings. This method can be used to analyze the schedulability of complex task sets which involve interrupts, certain synchronization protocols, non--preemptible sections and, in general, any mechanism that contributes to a complex priority structure. The method is illustrated with a realistic example.
BibTeX:
@inproceedings{Harbour1991,
  author = {Harbour, Michael Gonzalez and Klein, Mark H. and Lehoczky, John P.},
  title = {Fixed priority scheduling periodic tasks with varying execution priority},
  booktitle = {Proceedings of the 12th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1991},
  pages = {116--128},
  url = {papers/Harbour1991.pdf},
  doi = {http://doi.org/10.1109/REAL.1991.160365}
}
Hardy, D. Analyse pire cas pour processeur multi--cœurs disposant de caches partagés 2010 School: Université Européenne de Bretagne  phdthesis URL 
BibTeX:
@phdthesis{Hardy2010,
  author = {Hardy, Damien},
  title = {Analyse pire cas pour processeur multi--cœurs disposant de caches partagés},
  school = {Université Européenne de Bretagne},
  year = {2010},
  url = {papers/Hardy2010.pdf}
}
Henzinger, T.A., Horowitz, B. and Kirsch, C.M. Giotto: A Time--Triggered Language for Embedded Programming 2001
Vol. 2211Proceedings of the 1st International Workshop on Embedded Software (EMSOFT), pp. 166-184 
inproceedings DOI URL 
Abstract: Giotto provides an abstract programmer’s model for the implementation of embedded control systems with hard real--time constraints. A typical control application consists of periodic software tasks together with a mode switching logic for enabling and disabling tasks. Giotto specifies time-triggered sensor readings, task invocations, and mode switches independent of any implementation platform. Giotto can be annotated with platform constraints such as task-to-host mappings, and task and communication schedules. The annotations are directives for the Giotto compiler, but they do not alter the functionality and timing of a Giotto program. By separating the platform-independent from the platform-dependent concerns, Giotto enables a great deal of flexibility in choosing control platforms as well as a great deal of automation in the validation and synthesis of control software. The time-triggered nature of Giotto achieves timing predictability, which makes Giotto particularly suitable for safety-critical applications.
BibTeX:
@inproceedings{Henzinger2001,
  author = {Henzinger, Thomas A. and Horowitz, Benjamin and Kirsch, Christoph Meyer},
  title = {Giotto: A Time--Triggered Language for Embedded Programming},
  booktitle = {Proceedings of the 1st International Workshop on Embedded Software (EMSOFT)},
  publisher = {Springer},
  year = {2001},
  volume = {2211},
  pages = {166--184},
  url = {papers/Henzinger2001.pdf},
  doi = {http://doi.org/10.1007/3--540-45449-7_12}
}
Henzinger, T.A., Kirsch, C.M., Sanvido, M.A.A. and Pree, W. From control models to real--time code using Giotto 2003 IEEE Control Systems
Vol. 23(1), pp. 50-64 
article DOI URL 
Abstract: We present a methodology for control software development based on Giotto [2], a domain--specific high-level programming language for control applications. A Giotto program explicitly specifies the exact real-time interaction of software components with the physical world. The Giotto compiler automatically generates timing code that ensures the specified behavior on a given platform. This article illustrates the Giotto methodology by reimplementing the controller for an autonomously flying model helicopter originally developed at the Swiss Federal Institute of Technology (ETH) Zürich [3]. We demonstrate that Giotto introduces a negligible overhead and at the same time increases the reliability and reusability of the control software. The article begins with a conceptual overview of the Giotto methodology. We explain how Giotto helps to automate the control software development process and to improve the quality of the resulting code. We then report on the Giotto helicopter project. We use the autopilot software for the helicopter to guide an informal presentation of the Giotto language and of the Simulink/Giotto (S/G) translator, which extracts a Giotto program from a Giotto control model specified in Simulink. This is followed by a brief discussion of the compilation and execution of the Giotto-based control system. The article concludes with a summary of available Giotto implementations and pointers to related work.
BibTeX:
@article{Henzinger2003,
  author = {Henzinger, Thomas A. and Kirsch, Christoph Meyer and Sanvido, Marco A. A. and Pree, Wolfgang},
  title = {From control models to real--time code using Giotto},
  journal = {IEEE Control Systems},
  year = {2003},
  volume = {23},
  number = {1},
  pages = {50--64},
  url = {papers/Henzinger2003.pdf},
  doi = {http://doi.org/10.1109/MCS.2003.1172829}
}
Hermant, J.-F., Leboucher, L. and Rivierre, N. Real-time fixed and dynamic priority driven scheduling algorithms: theory and experience 1996 (RR-3081)School: INRIA  techreport URL 
Abstract: There are two main positions regarding real-time scheduling algorithms. The first is based on fixed priorities and the second makes use of dynamic priorities such as deadlines. These two approaches have never really been compared because the emphasis has always been on the ease of implementation rather than the efficiency of the algorithms and the complexity of the associated feasibility conditions. In addition to traditional real-time applications, we believe that starting to look at these two criteria will be very important from the point of view of providing admission control mechanisms and real-time guarantees on large distributed systems like the Internet network.
To that end, our purpose is first to provide ageneral framework based, on the one hand, a representation of preemptive, real-time scheduling in an algebraic structure that enables us to evaluate the distance of the optimality of any scheduling algorithm ; and on the other hand, a consistent representation of the associated feasibility conditions that enables us to evaluate the number of basic operations. As a second step, considering several kinds of traffics, we initiate the comparison by a straight, but limited, application of our general framework. Our preliminary results will notably highlight, in the cases where deadlines are all greater than periods, that fixed priority schedulers (like deadline monotonic) behave as well as EDF while the worst-case response time analysis is less complex. The same observation is valid when the task sets are almost homogeneous but is in favor of EDF in the general case or when a simple feasibility analysis is needed.
Therefore, it might be of interest, given a real-time scheduling context (spanning from small embedded systems to large distributed systems), to take into account these two extra criteria in order to find a right trade-off among several possible solutions.
BibTeX:
@techreport{Hermant1996,
  author = {Hermant, Jean-François and Leboucher, Laurent and Rivierre, Nicolas},
  title = {Real-time fixed and dynamic priority driven scheduling algorithms: theory and experience},
  school = {INRIA},
  year = {1996},
  number = {RR-3081},
  note = {Projet REFLECS},
  url = {papers/Hermant1996.pdf}
}
Hoang, H., Jonsson, M., Hagström, U. and Kallerdahl, A. Switched real--time Ethernet with earliest deadline first scheduling - protocols and traffic handling 2002 Parallel and Distributed Computing Practices (PDCP)
Vol. 5(1)Proceeding of the 16th International Parallel and Distributed Processing Symposium (IPDPS), pp. 105-115 
article  
Abstract: There is a strong interest of using the cheap and simple Ethernet technology for industrial and embedded systems. This far, however, the lack of real--time services has prevented this change of used network technology. This paper presents enhancements to full-duplex switched Ethernet for the ability of giving throughput and delay guarantees. The switch and the end-nodes controls the real-time traffic with Earliest Deadline First (EDF) scheduling on the frame level. No modification to the Ethernet standard is needed in the network that supports both real-time and non-real-time TCP/IP communication. The switch is responsible for admission control where feasibility analysis is made for each link between source and destination. The switch broadcasts Ethernet frames regularly to clock synchronize the end nodes and to implement flow control for non-real-time traffic.
BibTeX:
@article{Hoang2002,
  author = {Hoang, Hoai and Jonsson, Magnus and Hagström, Ulrik and Kallerdahl, Anders},
  title = {Switched real--time Ethernet with earliest deadline first scheduling - protocols and traffic handling},
  booktitle = {Proceeding of the 16th International Parallel and Distributed Processing Symposium (IPDPS)},
  journal = {Parallel and Distributed Computing Practices (PDCP)},
  year = {2002},
  volume = {5},
  number = {1},
  pages = {105--115}
}
Hohmuth, M. and Peter, M. Helping in a multiprocessor environment 2001 Proceeding of 2nd Workshop on Common Microkernel System Platforms, pp. 5  inproceedings URL 
Abstract: This report presents Fiasco--SMP, a port of the Fiasco microkernel to the multiprocessor-x86 architecture. We the discuss design principles we used, and the resulting design for remote-thread manipulation in Fiasco. In particular, we showhow we extended Fiasco’s implementation of priority inheritance to fit a multiprocessor environment. Our design has two desirable properties. First, it minimizes the number of inter-processor interrupts (IPIs) in thesystem. Second, for the normal (uncontented) case, it avoids synchronous inter-processor notifications (where one CPU needs to wait for the result of an IPI it sent to another CPU), thereby removing the effect of IPI latency on CPU-local execution—even when manipulating remote threads. Moreover, we propose an extension to the L4 interface that allows server threads to specify that the kernel is allowed to schedule them on a remote CPU (i. e., not on their home CPU) when they become runnable after an IPC. We believe that this behavior has advantages for an important class of servers as it cuts out IPI latency from the server-startup delay.
BibTeX:
@inproceedings{Hohmuth2001,
  author = {Hohmuth, Michael and Peter, Michael},
  title = {Helping in a multiprocessor environment},
  booktitle = {Proceeding of 2nd Workshop on Common Microkernel System Platforms},
  year = {2001},
  pages = {5},
  url = {papers/Hohmuth2001.pdf}
}
Holman, P.L. On the Implementation of Pfair--scheduled Multiprocessor Systems 2004 School: University of North Carolina  phdthesis URL 
Abstract: The goal of this dissertation is to extend the Pfair scheduling approach in order to enable its efficient implementation on a real--time multiprocessor. At present, Pfair scheduling is the only known means for optimally scheduling recurrent real-time tasks on multiprocessors. In addition, there has been growing practical interest in such approaches due to their fairness guarantees. Unfortunately, prior work in this area has considered only the scheduling of independent tasks, which do not communicate with each other or share resources. The work presented herein focuses both on adding support for these actions and also on developing techniques for reducing various forms of implementation overhead, including that produced by task migrations and context switches. The thesis of this dissertation is: tasks can be efficiently synchronized in Pfair-scheduled systems and overhead due to common system events, such as context switches and migrations, can be reduced. This thesis is established through research in three areas. First, the pre-existing Pfair scheduling theory is extended to support the scheduling of groups of tasks as a single entity. Second, mechanisms for supporting both lock-based and lock-free synchronization are presented. Lock-based synchronization coordinates access to shared resources through the use of semaphores. On the other hand, lock-free operations are optimistically attempted and then retried if the operation fails. Last, the deployment of Pfair scheduling on a symmetric multiprocessor is considered.
BibTeX:
@phdthesis{Holman2004,
  author = {Holman, Philip L.},
  title = {On the Implementation of Pfair--scheduled Multiprocessor Systems},
  school = {University of North Carolina},
  year = {2004},
  url = {www.cs.unc.edu/ anderson/diss/holmandiss.pdf}
}
Hou, E.S.H., Ansari, N. and Ren, H. A Genetic Algorithm for Multiprocessor Scheduling 1994 IEEE Transactions on Parallel and Distributed Systems
Vol. 5(2), pp. 113-120 
article DOI URL 
Abstract: The problem of multiprocessor scheduling can be stated as finding a schedule for ageneral task graph to be executed on a multiprocessor system so that the schedulelength can be minimized. This scheduling problem is known to be NP--hard, and methodsbased on heuristic search have been proposed to obtain optimal and suboptimal solutions.Genetic algorithms have recently received much attention as a class of robust stochasticsearch algorithms for various optimization problems. In this paper, an efficient methodbased on genetic algorithms is developed to solve the multiprocessor scheduling problem.The representation of the search node is based on the order of the tasks being executedin each individual processor. The genetic operator proposed is based on the precedencerelations between the tasks in the task graph. Simulation results comparing the proposedgenetic algorithm, the list scheduling algorithm, and the optimal schedule using randomtask graphs, and a robot inverse dynamics computational task graph are presented.
BibTeX:
@article{Hou1994,
  author = {Hou, Edwin S. H. and Ansari, Nirwan and Ren, Hong},
  title = {A Genetic Algorithm for Multiprocessor Scheduling},
  journal = {IEEE Transactions on Parallel and Distributed Systems},
  year = {1994},
  volume = {5},
  number = {2},
  pages = {113--120},
  url = {papers/Hou1994.pdf},
  doi = {http://doi.org/10.1109/71.265940}
}
Huang, H. Power and Thermal Aware Scheduling for Real--time Computing Systems 2012 School: Florida International University  phdthesis URL 
Abstract: Over the past few decades, we have been enjoying tremendous benefits thanks to the revolutionary advancement of computing systems, driven mainly by the remarkable semiconductor technology scaling and the increasingly complicated processor architecture. However, the exponentially increased transistor density has directly led to exponentially increased power consumption and dramatically elevated system temperature, which not only adversely impacts the system’s cost, performance and reliability, but also increases the leakage and thus the overall power consumption. Today, the power and thermal issues have posed enormous challenges and threaten to slow down the continuous evolvement of computer technology. Effective power/thermal--aware design techniques are urgently demanded, at all design abstraction levels, from the circuit-level, the logic-level, to the architectural-level and the system-level. In this dissertation, we present our research efforts to employ real-time scheduling techniques to solve the resource-constrained power/thermal-aware, design-optimization problems. In our research, we developed a set of simple yet accurate system-level models to capture the processor’s thermal dynamic as well as the interdependency of leakage power consumption, temperature, and supply voltage. Based on these models, we investigated the fundamental principles in power/thermal-aware scheduling, and developed real-time scheduling techniques targeting at a variety of design objectives, including peak temperature minimization, overall energy reduction, and performance maximization. The novelty of this work is that we integrate the cutting-edge research on power and thermal at the circuit and architectural-level into a set of accurate yet simplified system-level models, and are able to conduct system-level analysis and design based on these models. The theoretical study in this work serves as a solid foundation for the guidance of the power/thermal-aware scheduling algorithms development in practical computing systems.
BibTeX:
@phdthesis{Huang2012,
  author = {Huang, Huang},
  title = {Power and Thermal Aware Scheduling for Real--time Computing Systems},
  school = {Florida International University},
  year = {2012},
  url = {papers/Huang2012.pdf}
}
Jalle, J., Quiñones, E., Abella, J., Fossati, L., Zulianello, M. and Cazorla, F.J. A Dual--Criticality Memory Controller (DCmc): Proposal and Evaluation of a Space Case Study 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 207-217  inproceedings DOI URL 
BibTeX:
@inproceedings{Jalle2014,
  author = {Jalle, Javier and Quiñones, Eduardo and Abella, Jaume and Fossati, Luca and Zulianello, Marco and Cazorla, Francisco J.},
  title = {A Dual--Criticality Memory Controller (DCmc): Proposal and Evaluation of a Space Case Study},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {207--217},
  url = {papers/Jalle2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.23}
}
Jan, M., Camier, J.-S. and David, V. Scheduling safety--critical real-time bus accesses using Time-Constrained Automata   misc  
Abstract: Assuming that tasks have been allocated on CPUs, the difficulty in distributed safety--critical real-time systems is to ensure an optimal scheduling of network accesses. Over a bus architecture, a Time Division Multiple Access (TDMA) approach is classicaly chosen. However, in existing systems, the developer is still in charge of the sizing and the scheduling of network accesses, therefore increasing development costs. In this work, we claim that the network scheduling of bus accesses must be generated automatically by an off-line tool chain. We therefore present how we adapted Time-Constrained Automata (TCA) to model communication requirements, in the context of a multi-scale time-triggered execution model. In particular, we show how to compute these requierements based on the description of the timing-constraints for the execution of tasks. Then, we generate the scheduling of bus accesses through a linear programming approach over a TDMA protocol. Finally, we validate our approach by showing an implementation of these steps in our OASIS-D prototype, a tool chain for building distributed safety-critical real time systems.
BibTeX:
@misc{Jan,
  author = {Jan, Mathieu and Camier, Jean--Sylvain and David, Vincent},
  title = {Scheduling safety--critical real-time bus accesses using Time-Constrained Automata}
}
Jan, M., David, V., Lalande, J. and Pitel, M. Usage of the safety--oriented real-time OASIS approach to build deterministic protection relays 2010 Proceedings of the 5th International Symposium on Industrial Embedded Systems (SIES), pp. 128-135  inproceedings DOI URL 
Abstract: As any safety--related system, medium voltage protection relays have to comply with a Safety Integrated Level (SIL), as defined by the IEC 61508 standard. The safety-function of the software part of protection relays is first to detect any faults within the supervised power network, then ask the tripping of the circuit breakers in order to isolate the faulty portion of the network. However, it is required that detection and isolation of faults must occur within a given time, as specified by the IEC 60255 standard. Schneider Electric currently achieves the demonstration that a protection relay is performing its safety-function within such temporal constraints at the price of a costly phase of tests. The OASIS approach is a complete tool-chain to build safety-critical deterministic real-time systems, which enables the demonstration of the system timeliness. In this paper, we show how we apply the OASIS approach to build a deterministic protection relay system. We designed a software platform called OASISepam, based on an existing product from Schneider Electric, namely the Sepam 10. We show a preliminary evaluation of our implementation over a STR710 ARM-based board that runs the OASIS kernel. Notably, we show that the observed worst-case end-to-end detection time of OASISepam fulfils the specified constraint expressed in the design phase and translated in the OASIS programming model. Consequently, the temporal behaviour of protection relays is mastered, thus reducing application development costs and allowing the optimization of selectivity.
BibTeX:
@inproceedings{Jan2010,
  author = {Jan, Mathieu and David, Vincent and Lalande, Jimmy and Pitel, Maurice},
  title = {Usage of the safety--oriented real-time OASIS approach to build deterministic protection relays},
  booktitle = {Proceedings of the 5th International Symposium on Industrial Embedded Systems (SIES)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {128--135},
  url = {papers/Jan2010.pdf},
  doi = {http://doi.org/10.1109/SIES.2010.5551378}
}
Jiang, W., Jiang, K. and Ma, Y. Resource Allocation of Security--Critical Tasks with Statistically Guaranteed Energy Constraint 2012 Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 330-339  inproceedings DOI URL 
Abstract: In this paper, we are interested in resource allocation for energy constrained and security--critical embedded systems. Tasks in such systems need to be successfully executed under certain energy budget and be robust against serious security threatens. Different to former energy minimal scheduling problem, we introduce a new optimization problem for a set of tasks with energy constraint and multiple security choices. We present a dynamic programming based approximation algorithm to minimize the security risk of the system while statistically guaranteeing energy consumption constraints for given energy slack ratio. The proposed algorithm is very efficient in both time and space dimensions, and achieves good solutions. Extensive simulations demonstrate the superiority of our algorithm over other approaches.
BibTeX:
@inproceedings{Jiang2012,
  author = {Jiang, Wei and Jiang, Ke and Ma, Yue},
  title = {Resource Allocation of Security--Critical Tasks with Statistically Guaranteed Energy Constraint},
  booktitle = {Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {330--339},
  url = {papers/Jiang2012.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2012.34}
}
Joseph, M. and Pandya, P.K. Finding Response Times in a Real--Time System 1986 The Computer Journal
Vol. 29(5), pp. 390-395 
article DOI URL 
Abstract: There are two major performance issues in a real--time system where a processor has a set of devices connected to it at different priority levels. The first is to prove whether, for a given assignment of devices to priority levels, the system can handle its peak processing load without losing any inputs from the devices. The second is to determine the response time for each device. There may be several ways of assigning the devices to priority levels so that the peak processing load is met, but only some (or perhaps none) of these ways will also meet the response-time requirements for the devices. In this paper, we define a condition that must be met to handle the peak processing load and describe how exact worst-case response times can then be found. When the condition cannot be met, we show how the addition of buffers for inputs can be useful. Finally, we discuss the use of multiple processors in systems for real-time applications.
BibTeX:
@article{Joseph1986,
  author = {Joseph, Mathai and Pandya, Paritosh K.},
  title = {Finding Response Times in a Real--Time System},
  journal = {The Computer Journal},
  year = {1986},
  volume = {29},
  number = {5},
  pages = {390--395},
  url = {papers/Joseph1986.pdf},
  doi = {http://doi.org/10.1093/comjnl/29.5.390}
}
Kaiser, R. and Wagner, S. Evolution of the PikeOS Microkernel 2007 Proceedings of the 1st International Workshop on Microkernels for Embedded Systems (MIKES), pp. 50-57  inproceedings URL 
Abstract: The PikeOS microkernel is targeted at real-time embedded systems. Its main goal is to provide a partitioned environment for multiple operating systems with different design goals to coexist in a single machine. It was initially modelled after the L4 microkernel and has gradually evolved over the years of its application to the real-time, embedded systems space. This paper describes the concepts that were added or removed during this evolution and it provides the rationale behind these design decisions.
BibTeX:
@inproceedings{Kaiser2007,
  author = {Kaiser, Robert and Wagner, Stephan},
  title = {Evolution of the PikeOS Microkernel},
  booktitle = {Proceedings of the 1st International Workshop on Microkernels for Embedded Systems (MIKES)},
  year = {2007},
  pages = {50--57},
  url = {/papers/Kaiser2007.pdf}
}
Kato, S. Reat--Time Scheduling of Periodic and Aperiodic Tasks on Multiprocessor Systems 2008 School: Keio University  phdthesis URL 
Abstract: Real--time scheduling techniques for multiprocessor systems have attracted considerable attention in recent years. However, the theoretical intricateness of scheduling periodic tasks raises a controversial trade-off that improving a system utilization with guaranteeing timing constraints of periodic tasks leads to more task preemptions and migrations. In addition, the subject of scheduling aperiodic tasks has not been considered very much. The research established herein considers the efficient scheduling of both periodic and aperiodic tasks on multiprocessor systems. The dissertation first presents the portioned scheduling technique for improving the schedulability to periodic tasks with a small number of task preemptions and migrations. Like the traditional partitioned scheduling, most of tasks are scheduled on dedicated processors with no migrations, however the portioned scheduling differs in that special tasks are permitted to migrate within the restricted range. The RMDP algorithm is developed for the discipline of static-priority scheduling, in which the traditional Rate Monotonic algorithm is combined with the portioned scheduling. The EDDHP algorithm is then devised for the discipline of dynamic-priority scheduling, in which the traditional Earliest Deadline First algorithm is combined. Finally, the EDDP algorithm is invented by extending the prioritization policy of the EDDHP algorithm to improve the worst-case system utilization with a guarantee of timing constraints. The dissertation also presents the global dispatch technique and the temporalmigration technique for enhancing the responsiveness to aperiodic tasks without jeopardizing periodic timing constraints. An aperiodic task is dispatched to a processor on which the response time is estimated to be minimized, and then periodic tasks with higher priorities are temporarily migrated onto different processors to moreover reduce the response time. The design of the traditional Priority Exchange algorithm and the Total Bandwidth Server algorithm is considered, in which the presented techniques are applied. Beyond the theoretical analysis for the worst case, the effectiveness of the developed scheduling algorithms for general cases is also studied by several sets of simulations.
BibTeX:
@phdthesis{Kato2008c,
  author = {Kato, Shinpei},
  title = {Reat--Time Scheduling of Periodic and Aperiodic Tasks on Multiprocessor Systems},
  school = {Keio University},
  year = {2008},
  url = {papers/Kato2008c.pdf}
}
Kato, S. and Ishikawa, Y. Gang EDF Scheduling of Parallel Task Systems 2009 Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS), pp. 459-468  inproceedings URL 
Abstract: The preemptive real--time scheduling of sporadic parallel task systems is studied. We present an algorithm, called Gang EDF, which applies the Earliest Deadline First (EDF) policy to the traditional Gang scheduling scheme. We alsoprovide schedulability analysis of Gang EDF. Specifically, the total amount of interference that is necessary to cause a deadline miss is first identified. The contribution of each task to the interference is then bounded. Finally, verifying that the total amount of contribution does not exceed the necessary interference for every task, the schedulability test is derived. Although the techniques proposed herein are based on the prior results for the sequential task model, we introduce new ideas for the parallel task model.
BibTeX:
@inproceedings{Kato2009c,
  author = {Kato, Shinpei and Ishikawa, Yutaka},
  title = {Gang EDF Scheduling of Parallel Task Systems},
  booktitle = {Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {459--468},
  url = {papers/Kato2009c.pdf}
}
Kato, S., Rajkumar, R."R. and Ishikawa, Y. A Loadable Real--Time Scheduler Suite for Multicore Platforms 2009 School: Department of Electrical and Computer Engineering, Carnegie Mellon University. Department of Computer Science, The University of Tokyo  techreport URL 
Abstract: Linux has received considerable attention in the embedded real--time systems domain recently, given that rich software libraries and device drivers are available. An issue of concern is, however, that the Linux kernel is not very capable of satisfying real-time systems requirements, particularly in the multicore context. In this paper, we present a loadable REal-time SCHeduler suite for Linux, called RESCH. RESCH supports easy installation of variant scheduling algorithms as plugins into Linux without any kernel patches, regardless of kernel configurations. We design and implement four scheduler plugins with different scheduling algorithms, corresponding to the state-of-the-art partitioned, semi-partitioned, and global scheduling techniques for multicore platforms. We also develop a Schedulability Benchmarking tool, called SchedBench, to evaluate the actual runtime schedulability of these scheduler plugins. Experiments demonstrate that the scheduler plugins boost schedulability for both arbitrary and harmonic periods, as compared to the native Linux scheduler. Particularly, the scheduler plugin based on semipartitioned scheduling achieves better performance in most cases, but the one based on partitioned scheduling is also competitive in the harmonic cases. Meanwhile, the ones based on global scheduling are often inferior to them, and do not receive benefit from the harmonicity very much.
BibTeX:
@techreport{Kato2009b,
  author = {Kato, Shinpei and Rajkumar, Ragunathan "Raj" and Ishikawa, Yutaka},
  title = {A Loadable Real--Time Scheduler Suite for Multicore Platforms},
  school = {Department of Electrical and Computer Engineering, Carnegie Mellon University. Department of Computer Science, The University of Tokyo},
  year = {2009},
  url = {papers/Kato2009b.pdf}
}
Kato, S. and Yamasaki, N. Global EDF--based Scheduling with Laxity-driven Priority Promotion 2011 Elsevier Journal of Systems Architecture
Vol. 57(5), pp. 498-517 
article DOI URL 
Abstract: This paper presents an algorithm, called Earliest Deadline Critical Laxity (EDCL), for scheduling sporadic task systems on multiprocessors. EDCL is a derivative of the Earliest Deadline Zero Laxity (EDZL) algorithm. Each job is assigned a priority based on the well--known Global Earliest Deadline First (G-EDF) algorithm, as long as its laxity – the amount of time from the earliest possible time of job completion to the deadline of job – is above a certain value. The priority is however promoted to the highest level once the laxity falls below this certain value in order to meet the deadline. Priority promotions are aligned with arrivals and completions of jobs under EDCL to avoid additional scheduler invocations, while EDZL can promote priorities arbitrarily. As compared with EDZL, EDCL reduces runtime overhead and implementation cost, but still strictly dominates G-EDF in schedulability. Schedulability tests for EDCL are derived through theoretical analysis, and sustainability properties are also considered. Our simulation results demonstrate that EDCL is competitive to EDZL in schedulability with a smaller number of scheduler invocations, and it also outperforms traditional EDF-based algorithms.
BibTeX:
@article{Kato2011,
  author = {Kato, Shinpei and Yamasaki, Nobuyuki},
  title = {Global EDF--based Scheduling with Laxity-driven Priority Promotion},
  journal = {Elsevier Journal of Systems Architecture},
  year = {2011},
  volume = {57},
  number = {5},
  pages = {498--517},
  url = {papers/Kato2011.pdf},
  doi = {http://doi.org/10.1016/j.sysarc.2011.01.002}
}
Kato, S. and Yamasaki, N. Semi--Partitioned Fixed-Priority Scheduling on Multiprocessors 2009 Proceedings of the 15th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS), pp. 23-32  inproceedings DOI URL 
Abstract: This paper presents a new algorithm for fixed--priority scheduling of sporadic task systems on multiprocessors. The algorithm is categorized to such a scheduling class that qualifies a few tasks to migrate across processors, while most tasks are fixed to particular processors. We design the algorithm so that a task is qualified to migrate, only if it cannot be assigned to any individual processors, in such a way that it is never returned to the same processor within the same period, once it is migrated from one processor to another processor. The scheduling policy is then conformed to DeadlineMonotonic. According to the simulation results, the new algorithm significantly outperforms the traditional fixed-priority algorithms in terms of schedulability.
BibTeX:
@inproceedings{Kato2009,
  author = {Kato, Shinpei and Yamasaki, Nobuyuki},
  title = {Semi--Partitioned Fixed-Priority Scheduling on Multiprocessors},
  booktitle = {Proceedings of the 15th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {23--32},
  url = {papers/Kato2009.pdf},
  doi = {http://doi.org/10.1109/RTAS.2009.9}
}
Kato, S. and Yamasaki, N. Portioned EDF--based Scheduling on Multiprocessors 2008 Proceedings of the ACM International Conference on Embedded Software (EMSOFT), pp. 10pp  inproceedings URL 
Abstract: This paper presents an EDF--based algorithm, called Earliest Deadline Deferrable Portion (EDDP), for efficient scheduling of recurrent real-time tasks on multiprocessor systems. The design of EDDP is based on the portioned scheduling technique which classifies each task into a fixed task or a migratable task. A fixed task is scheduled on the dedicated processor without migrations. A migratable task is meanwhile permitted to migrate between the particular two processors. In order to curb the cost of task migrations, EDDP makes at most M − 1 migratable tasks on M processors. The scheduling analysis derives the condition for a given task set to be schedulable. It is also proven that no tasks ever miss deadlines, if the system utilization does not exceed 65%. Beyond the theoretical analysis, the effectiveness of EDDP is evaluated through simulation studies. Simulation results show that EDDP achieves high system utilization with a small number of preemptions, compared with the traditional EDF-based algorithms.
BibTeX:
@inproceedings{Kato2008a,
  author = {Kato, Shinpei and Yamasaki, Nobuyuki},
  title = {Portioned EDF--based Scheduling on Multiprocessors},
  booktitle = {Proceedings of the ACM International Conference on Embedded Software (EMSOFT)},
  publisher = {ACM},
  year = {2008},
  pages = {10pp},
  url = {papers/Kato2008a.pdf}
}
Kato, S. and Yamasaki, N. Portioned Static--Priority Scheduling on Multiprocessors 2008 Proceedings of the 22th IEEE International Parallel and Distributed Processing Symposium (IPDPS), pp. 1-12  inproceedings DOI URL 
Abstract: This paper proposes an efficient real--time scheduling algorithm for multiprocessor platforms. The algorithm is a derivative of the Rate Monotonic (RM) algorithm, with its basis on the portioned scheduling technique. The theoretical design of the algorithmis well implementable for practical use. The schedulability of the algorithm is also analyzed to guarantee the worst-case performance. The simulation results show that the algorithm achieves higher system utilizations, in which all tasks meet deadlines, with a small number of preemptions compared to traditional algorithms.
BibTeX:
@inproceedings{Kato2008b,
  author = {Kato, Shinpei and Yamasaki, Nobuyuki},
  title = {Portioned Static--Priority Scheduling on Multiprocessors},
  booktitle = {Proceedings of the 22th IEEE International Parallel and Distributed Processing Symposium (IPDPS)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {1--12},
  url = {papers/Kato2008b.pdf},
  doi = {http://doi.org/10.1109/IPDPS.2008.4536299}
}
Kato, S. and Yamasaki, N. Semi--Partitioning Technique for Multiprocessor Real-Time Scheduling 2008 Proceedings of the Work--in-Progress Session of the 29th IEEE Real-Time Systems Symposium (WiP RTSS), pp. 4pp  inproceedings URL 
Abstract: A semi--partitioning technique is presented for efficient scheduling of sporadic task systems on multiprocessors. The presented technique performs in the same manner as the traditional partitioning, as long as tasks are successfully partitioned, but a task is allowed to be shared among multiple processors for its execution, if a spare capacity of every individual processor is not enough to accept the full execution of the task, beyond partitioning. We also design an EDF-based algorithm in which the semi-partitioning technique is combined. According to the simulation results, the presented semi-partitioning approach improves schedulable multiprocessor utilization by 10 to 30 over the traditional partitioning approach.
BibTeX:
@inproceedings{Kato2008,
  author = {Kato, Shinpei and Yamasaki, Nobuyuki},
  title = {Semi--Partitioning Technique for Multiprocessor Real-Time Scheduling},
  booktitle = {Proceedings of the Work--in-Progress Session of the 29th IEEE Real-Time Systems Symposium (WiP RTSS)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {4pp},
  url = {papers/Kato2008.pdf}
}
Kato, S. and Yamasaki, N. Real--Time Scheduling with Task Splitting on Multiprocessors 2007 Proceedings of the 13th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 441-450  inproceedings DOI URL 
Abstract: This paper presents a real--time scheduling algorithm with high schedulability and few preemptions for multiprocessor systems. The algorithm is based on an unorthodox method called portionedf scheduling that assigns each task to a particular processor like partitioned scheduling but can split a task into two processors if there is not enough capacity remaining on a processor. We describe an algorithm for assigning tasks to processors as well as an algorithm for scheduling the assigned tasks on per-processor. The schedulability analysis provides a formula to calculate the upper bound of the schedulable per-processor utilization for the algorithm. We then prove that the least upper bound of the whole system utilization is 50%. In addition, we propose heuristic procedures to improve schedulability. The simulation results show that the algorithm can often successfully schedule a task set with system utilization much higher than 50 though the least upper bound is 50%. We also show that the algorithm achieves higher schedulability with fewer preemptions compared to the existiting algorithms.
BibTeX:
@inproceedings{Kato2007,
  author = {Kato, Shinpei and Yamasaki, Nobuyuki},
  title = {Real--Time Scheduling with Task Splitting on Multiprocessors},
  booktitle = {Proceedings of the 13th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {441--450},
  url = {papers/Kato2007.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2007.61}
}
Kato, S., Yamasaki, N. and Ishikawa, Y. Semi--Partitioned Scheduling of Sporadic Task Systems on Multiprocessors 2009 Proceedings of the 21st Euromicro Conference on Real--time Systems (ECRTS), pp. 249-258  inproceedings DOI URL 
Abstract: This paper presents a new algorithm for scheduling of sporadic task systems with arbitrary deadlines on identical multiprocessor platforms. The algorithm is based on the concept of semi--partitioned scheduling, in which most tasks are fixed to specific processors, while a few tasks migrate across processors. Particularly, we design the algorithm so that tasks are qualified to migrate only if a task set cannot be partitioned any more, and such migratory tasks migrate from one processor to another processor only once in each period. The scheduling policy is then subject to Earliest Deadline First. Simulation results show that the algorithm delivers competitive scheduling performance to the state-of-the-art, with a smaller number of context switches.
BibTeX:
@inproceedings{Kato2009a,
  author = {Kato, Shinpei and Yamasaki, Nobuyuki and Ishikawa, Yutaka},
  title = {Semi--Partitioned Scheduling of Sporadic Task Systems on Multiprocessors},
  booktitle = {Proceedings of the 21st Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {249--258},
  url = {papers/Kato2009a.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2009.22}
}
Kemayo, G., Ridouard, F., Bauer, H. and Richard, P. Optimistic problems in the trajectory approach in FIFO context 2013 Proceedings of the 18th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA)  inproceedings URL 
Abstract: AFDX (Avionics Full Duplex Switched Ethernet) is a network designed for safety--critical applications in avionics systems. The flow analysis is mandatory for the certification. The end-to-end (ETE) delay upper bound has to be computed and hence guaranteed. Different approaches have been proposed to compute ETE delay upper bound such as the Network Calculus and the trajectory method. Both methods are deemed to introduce some pessimism in the computations. We only focus next on the trajectory approach. This paper shows that the original trajectory approach is flawed and can compute an optimistic ETE. We present a counter-example and discuss the sources of optimism that must be considered to revise the trajectory method.
BibTeX:
@inproceedings{Kemayo2013,
  author = {Kemayo, Georges and Ridouard, Frédéric and Bauer, Henri and Richard, Pascal},
  title = {Optimistic problems in the trajectory approach in FIFO context},
  booktitle = {Proceedings of the 18th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA)},
  publisher = {IEEE Computer Society},
  year = {2013},
  url = {papers/Kemayo2013.pdf}
}
Kim, E., Shin, K.G. and Lee, J. Real--Time Discharge/Charge Rate Management for Hybrid Energy Storage in Electric Vehicles 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 228-237  inproceedings DOI URL 
Abstract: Electric vehicles (EVs) are usually powered by a large number of battery cells, necessitating an effective battery management system (BMS) which protects the battery cells from harsh conditions while providing the required power efficiently. The discharge/charge rate of battery cells affects their health significantly, and existing BMSes employ simple discharge/charge rate scheduling so as to prevent weak cells from being discharged/charged excessively.
In this paper, we design and evaluate the real--time management of battery discharge/charge rate to extend the life of batteries in powering EVs based on their physical dynamics and operation history. We first explore a contemporary energy storage system for EVs to capture its physical dynamics that affect the battery discharge/charge rate; for example, a regenerative braking system for reusing the dissipated energy leads to current surges into the batteries, which shortens battery life. Based on understanding of the effects of discharge/charge rate in an energy storage system, we first devise control knobs for manipulating the discharge/charge rate. Then, we design an adaptive algorithm that manages the discharge/charge rate by determining the control knobs with a reconfigurable energy storage architecture. Our in-depth evaluation demonstrates that the proposed discharge/charge rate management improves battery life up to 37.7% at little additional cost compared to the existing energy storage systems.
BibTeX:
@inproceedings{Kim2014a,
  author = {Kim, Eugene and Shin, Kang G. and Lee, Jinkyu},
  title = {Real--Time Discharge/Charge Rate Management for Hybrid Energy Storage in Electric Vehicles},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {228--237},
  url = {papers/Kim2014a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.16}
}
Kim, H., Wang, S. and Rajkumar, R."R. vMPCP: a Synchronization Framework for Multi--core Virtual Machines 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 86-95  inproceedings DOI URL 
Abstract: The virtualization of real--time systems has received much attention for its many benefits, such as the consolidation of individually developed real-time applications while maintaining their implementations. However, the current state of the art still lacks properties required for resource sharing among real-time application tasks in a multi-core virtualization environment. In this paper, we propose vMPCP, a synchronization framework for the virtualization of multi-core real-time systems. vMPCP exposes the executions of critical sections of tasks in a guest virtual machine to the hypervisor. Using this approach, vMPCP reduces and bounds blocking time on accessing resources shared within and across virtual CPUs (VCPUs) assigned on different physical CPU cores. vMPCP supports periodic server and deferrable server policies for the VCPU budget replenish policy, with an optional budget overrun to reduce blocking times. We provide the VCPU and task schedulability analyses under vMPCP, with different VCPU budget supply policies, with and without overrun. Experimental results indicate that, under vMPCP, deferrableserver outperforms periodic server when overrun is used, with as much as 80% more tasksets being schedulable. The case study using our hypervisor implementation shows that vMPCP yields significant benefits compared to a virtualization-unaware multi-core synchronization protocol, with 29% shorter response time on average.
BibTeX:
@inproceedings{Kim2014,
  author = {Kim, Hyoseung and Wang, Shige and Rajkumar, Ragunathan "Raj"},
  title = {vMPCP: a Synchronization Framework for Multi--core Virtual Machines},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {86--95},
  url = {papers/Kim2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.11}
}
Kim, W., Kim, J. and Min, S.L. A Dynamic Voltage Scaling Algorithm for Dynamic--Priority Hard Real-Time Systems Using Slack Time Analysis 2002 Proceedings of the Conference on Design, Automation and Test in Europe (DATE), pp. 788-794  inproceedings URL 
Abstract: Dynamic voltage scaling (DVS), which adjusts the clockspeed and supply voltage dynamically, is an effective techniquein reducing the energy consumption of embedded real--timesystems. The energy efficiency of a DVS algorithm largelydepends on the performance of the slack estimation methodused in it. In this paper, we propose a novel DVS algorithmfor periodic hard real-time tasks based on an improved slackestimation algorithm. Unlike the existing techniques, the proposedmethod takes full advantage of the periodic characteristicsof the real-time tasks under priority-driven schedulingsuch as EDF. Experimental results show that the proposed algorithmreduces the energy consumption by 20 40% over theexisting DVS algorithm. The experiment results also show thatour algorithm based on the improved slack estimation methodgives comparable energy savings to the DVS algorithm basedon the theoretically optimal (but impractical) slack estimationmethod.
BibTeX:
@inproceedings{Kim2002,
  author = {Kim, Woonseok and Kim, Jihong and Min, Sang Lyul},
  title = {A Dynamic Voltage Scaling Algorithm for Dynamic--Priority Hard Real-Time Systems Using Slack Time Analysis},
  booktitle = {Proceedings of the Conference on Design, Automation and Test in Europe (DATE)},
  publisher = {IEEE Computer Society},
  year = {2002},
  pages = {788--794},
  url = {papers/Kim2002.pdf}
}
Kirkpatrick, S., Gelatt, C.D. and Vecchi, M.P. Optimization by Simulated Annealing 1983 Science
Vol. 220(4598), pp. 671-680 
article URL 
Abstract: There is a deep and useful connection between statistical mechanics (the behavior of systems with many degrees of freedom in thermal equilibrium at a finite temperature) and multivariate or combinatorial optimization (finding the minimum of a given function depending on many parameters). A detailed analogy with annealing in solids provides a framework for optimization of the properties of very large and complex systems. This connection to statistical mechanics exposes new information and provides an unfamiliar perspective on traditional optimization problems and methods.
BibTeX:
@article{Kirkpatrick1983,
  author = {Kirkpatrick, Scott and Gelatt, C. D. and Vecchi, Mario P.},
  title = {Optimization by Simulated Annealing},
  journal = {Science},
  year = {1983},
  volume = {220},
  number = {4598},
  pages = {671--680},
  url = {papers/Kirkpatrick1983.pdf}
}
Kirsch, C.M., Sanvido, M.A.A. and Henzinger, T.A. A Programmable Microkernel for Real--Time Systems 2005 Proceedings of the 1st International Conference on Virtual Execution Environments (VEE), pp. 35-45  inproceedings DOI URL 
Abstract: We present a new software system architecture for the implementation of hard real--time applications. The core of the system is a microkernel whose reactivity (interrupt handling as in synchronous reactive programs) and proactivity (task scheduling as in traditional RTOSs) are fully programmable. The microkernel, which we implemented on a Strong-ARM processor, consists of two interacting domain-specific virtual machines, a reactive E (Embedded) machine and a proactive S (Scheduling) machine. The microkernel code (or microcode) that runs on the microkernel is partitioned into E and S code. E code manages the interaction of the system with the physical environment: the execution of E code is triggered by environment interrupts, which signal external events such as the arrival of a message or sensor value, and it releases application tasks to the S machine. S code manages the interaction of the system with the processor: the execution of S code is triggered by hardware interrupts, which signal internal events such as the completion of a task or time slice, and it dispatches application tasks to the CPU, possibly preempting a running task. This partition of the system orthogonalizes the two main concerns of real-time implementations: E code refers to environment time and thus defines the reactivity of the system in a hardware- and scheduler-independent fashion; S code refers to CPU time and defines a system scheduler. If both time lines can be reconciled, then the code is called time safe; violations of time safety are handled again in a programmable way, by run-time exceptions. The separation of E from S code permits the independent programming, verification, optimization, composition, dynamic adaptation, and reuse of both reaction and scheduling mechanisms. Our measurements show that the system overhead is very acceptable even for large sets of task, generally in the 0.2–0.3% range.
BibTeX:
@inproceedings{Kirsch2005,
  author = {Kirsch, Christoph Meyer and Sanvido, Marco A. A. and Henzinger, Thomas A.},
  title = {A Programmable Microkernel for Real--Time Systems},
  booktitle = {Proceedings of the 1st International Conference on Virtual Execution Environments (VEE)},
  publisher = {ACM},
  year = {2005},
  pages = {35--45},
  url = {papers/Kirsch2005.pdf},
  doi = {http://doi.org/10.1145/1064979.1064986}
}
Kivity, A., Kamay, Y., Laor, D., Lublin, U. and Liguori, A. kvm: the Linux Virtual Machine Monitor 2007 Proceedings of the Ottawa Linux Symposium (OLS), pp. 225-230  inproceedings URL 
Abstract: Virtualization is a hot topic in operating systems these days. It is useful in many scenarios: server consolidation, virtual test environments, and for Linux enthusiasts who still can not decide which distribution is best. Recently, hardware vendors of commodity x86 processors have added virtualization extensions to the instruction set that can be utilized to write relatively simple virtual machine monitors.
The Kernel-based Virtual Machine, or kvm, is a new Linux subsystem which leverages these virtualization extensions to add a virtual machine monitor (or hypervisor) capability to Linux. Using kvm, one can create and run multiple virtual machines. These virtual machines appear as normal Linux processes and integrate seamlessly with the rest of the system.
BibTeX:
@inproceedings{Kivity2007,
  author = {Kivity, Avi and Kamay, Yaniv and Laor, Dor and Lublin, Uri and Liguori, Anthony},
  title = {kvm: the Linux Virtual Machine Monitor},
  booktitle = {Proceedings of the Ottawa Linux Symposium (OLS)},
  year = {2007},
  pages = {225--230},
  url = {papers/Kivity2007.pdf}
}
Kooti, H., Dang, N., Mishra, D. and Bozorgzadeh, E. Energy Budget Management for Energy Harvesting Embedded Systems 2012 Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 320-329  inproceedings DOI URL 
Abstract: In battery--powered embedded systems, the limit of battery charge creates a challenge in scheduling tasks to meet both their deadlines and Quality of Service (QoS) requirements. Harvesting energy from the surrounding environment continuously eliminates the concern of limited battery charge. However, the uncertainty in availability of energy brings challenges in embedded systems. In this paper, we propose an energy management technique to maximize QoS of the system. Our technique is composed of two steps: an offline step and an online step. In the offline step we use frame-based energy harvesting prediction in one harvesting period, in order to find the best QoS level for the tasks and maximize the energy utilization. The information provided from the offline step guides the online scheduler to decide about job scheduling at run-time to minimize the QoS violation. We compared our scheduler with other approaches and on average we reduce the violation count by 22%.
BibTeX:
@inproceedings{Kooti2012,
  author = {Kooti, Hessam and Dang, Nga and Mishra, Deepak and Bozorgzadeh, Eli},
  title = {Energy Budget Management for Energy Harvesting Embedded Systems},
  booktitle = {Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {320--329},
  url = {papers/Kooti2012.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2012.38}
}
Kopetz, H. The time--triggered model of computation 1998 Proceedings of the 19th IEEE Real--Time Systems Symposium (RTSS), pp. 168-177  inproceedings DOI URL 
Abstract: The Time--Triggered (TT) model of computation is a model for the representation and analysis of the design of large hard real time systems. Central to this model is the concept of temporal accuracy of real time information. The TT model consists of four building blocks, interfaces that contain temporally accurate data, a communication subsystem that connects interfaces, a host computer that reads input data from interfaces and writes output data to interfaces and a transducer that transforms the information representation in the environment into the digital form of the interface and vice versa. These four building blocks can be used recursively to describe arbitrary large hard real time systems. The TT model separates cleanly the design of the interaction pattern among components from the design of the components themselves. It thus supports a compositional design. In the final section the TT model is compared to the client server model
BibTeX:
@inproceedings{Kopetz1998,
  author = {Kopetz, Hermann},
  title = {The time--triggered model of computation},
  booktitle = {Proceedings of the 19th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1998},
  pages = {168--177},
  url = {papers/Kopetz1998.pdf},
  doi = {http://doi.org/10.1109/REAL.1998.739743}
}
Kopetz, H. Should Responsive Systems be Event--Triggered or Time-Triggered ? 1993 IEICE Transactions on Information and Systems
Vol. E76--D(11), pp. 1325-1332 
article URL 
Abstract: In this paper the two different paradigms for the design of responsive, i.e., distributed fault--tolerant real-time systems, the event-triggered (ET) approach and the time-triggered (TT) approach, are analyzed and compared. The comparison focuses on the temporal properties and considers the issues of predictability, testability, resource utilization, extensibility, and assumption coverage.
BibTeX:
@article{Kopetz1993,
  author = {Kopetz, Hermann},
  title = {Should Responsive Systems be Event--Triggered or Time-Triggered ?},
  journal = {IEICE Transactions on Information and Systems},
  year = {1993},
  volume = {E76--D},
  number = {11},
  pages = {1325--1332},
  url = {papers/Kopetz1993.pdf}
}
Kopetz, H., Braun, M., Ebner, C., Krüger, A., Millinger, D., Nossal, R. and Schedl, A.V. The Design of Large Real--Time Systems: The Time-Triggered Approach 1995 Proceedings of the 16th IEEE Real--Time Systems Symposium (RTSS), pp. 182-187  inproceedings DOI URL 
Abstract: The time--triggered (TT) architecture approach supports the spatial partitioning of a large, distributed real-time system into a set of autonomous subsystems with small control-free data-sharing interfaces between them. This paper presents such a TT architecture and gives a detailed description of the interface between an autonomous time-triggered communication subsystem based on the TTP protocol and the host computer within a node of this architecture. This interface acts as a temporal firewall that eliminates the possibility of control error propagation from one subsystem to another subsystem. It thus facilitates the independent development and validation of the subsystems and supports the composability of the distributed architecture with respect to timeliness, validation, and certification.
BibTeX:
@inproceedings{Kopetz1995,
  author = {Kopetz, Hermann and Braun, Martin and Ebner, Christian and Krüger, Andreas and Millinger, Dietmar and Nossal, Roman and Schedl, Anton V.},
  title = {The Design of Large Real--Time Systems: The Time-Triggered Approach},
  booktitle = {Proceedings of the 16th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1995},
  pages = {182--187},
  url = {papers/Kopetz1995.pdf},
  doi = {http://doi.org/10.1109/REAL.1995.495208}
}
Kopetz, H., Damm, A., Koza, C., Mulazzani, M., Schwbl, W., Senft, C. and Zailinger, R. Distributed fault--tolerant real-time systems: the Mars approach 1989 IEEE Micro
Vol. 9(1), pp. 25-40 
article DOI URL 
Abstract: The authors describe the Maintainable Real--Time System, a fault-tolerant distributed system for process control, developed under the Mars project started in 1980 at the Technische Universitat Berlin. They explore the characteristics of distributed real-time systems and then present the Mars approach to real-time process control, its architectural design and implementation, and one of its applications. The authors focus on the maintainability of the Mars architecture, describe the Mars operating system, and discuss timing analysis. The control of a rolling mill that produces metal plates and bars is examined.
BibTeX:
@article{Kopetz1989,
  author = {Kopetz, Hermann and Damm, Andreas and Koza, Christian and Mulazzani, Marco and Schwbl, Wolfgang and Senft, Christoph and Zailinger, Ralph},
  title = {Distributed fault--tolerant real-time systems: the Mars approach},
  journal = {IEEE Micro},
  year = {1989},
  volume = {9},
  number = {1},
  pages = {25--40},
  url = {papers/Kopetz1989.pdf},
  doi = {http://doi.org/10.1109/40.16792}
}
Kopetz, H., Laprie, J.-C., Randell, B. and Littlewood, B. Predictably Dependable Computing Systems 1995   book  
BibTeX:
@book{Kopetz1995a,
  author = {Kopetz, Hermann and Laprie, Jean--Claude and Randell, Brian and Littlewood, Bev},
  title = {Predictably Dependable Computing Systems},
  publisher = {Springer--Verlag New York, Inc.},
  year = {1995}
}
Kopetz, H., Zailinger, R., Fohler, G., Kantz, H., Puschner, P.P. and Schütz, W. The design of real--time systems: from specification to implementation and verification 1991 Software Engineering Journal
Vol. 6(3), pp. 72-82 
article URL 
Abstract: This paper presents an engineering approach to the design of distributed real--time systems, which guarantee hard deadlines and can tolerate a specified set of faults. The methodology covers the stepwise refinement of the given requirements, expressed in the form of real-time transactions, to task and protocol executions. It also includes a timing analysis and dependability evaluation of the still incomplete design. The testability of the evolving system is considered to be of essential concern. A set of coherent tools for the support of the methodology is described in some detail. The methodology assumes that the runtime architecture is based on static scheduling, and a globally synchronised time-base is available to co-ordinate the system actions in the domain of real time.
BibTeX:
@article{Kopetz1991,
  author = {Kopetz, Hermann and Zailinger, Ralph and Fohler, Gerhard and Kantz, Heinz and Puschner, Peter P. and Schütz, Werber},
  title = {The design of real--time systems: from specification to implementation and verification},
  journal = {Software Engineering Journal},
  year = {1991},
  volume = {6},
  number = {3},
  pages = {72--82},
  url = {papers/Kopetz1991.pdf}
}
Krcal, P., Stigge, M. and Yi, W. Multi--processor Schedulability Analysis of Preemptive Real-Time Tasks with Variable Execution Times 2007
Vol. 4763Formal Modeling and Analysis of Timed Systems, pp. 274-289 
incollection DOI URL 
Abstract: In this paper, we study schedulability analysis problems for multi--processor real-time systems. Assume a set of real-time tasks whose execution times and deadlines are known. We use timed automata to describe the non-deterministic arrival times of tasks. The schedulability problem is to check whether the released task instances can be executed within their given deadlines on a multi-processor platform where each processor has a task queue to buffer task instances scheduled to run on the processor. On the positive side, we show that the problem is decidable for systems with non-preemptive schedulers or tasks with fixed execution times. A surprising negative result is that for multi-processor systems with variable task execution times and a preemptive scheduler, the schedulability analysis problem is undecidable, which is still an open problem in the single-processor setting.
BibTeX:
@incollection{Krcal2007,
  author = {Krcal, Pavel and Stigge, Martin and Yi, Wang},
  title = {Multi--processor Schedulability Analysis of Preemptive Real-Time Tasks with Variable Execution Times},
  booktitle = {Formal Modeling and Analysis of Timed Systems},
  publisher = {Springer Berlin / Heidelberg},
  year = {2007},
  volume = {4763},
  pages = {274--289},
  url = {papers/Krcal2007.pdf},
  doi = {http://doi.org/10.1007/978--3-540-75454-1_20}
}
Kumar, P., Stoimenov, N. and Thiele, L. An Algorithm for Online Reconfiguration of Resource Reservations for Hard Real--Time Systems 2012 Proceedings of the 24th Euromicro Conference on Real--Time Systems (ECRTS), pp. 245-254  inproceedings DOI URL 
Abstract: Nowadays, real--time applications expect the supporting computing system to be reconfigured at run-time. Even during such reconfiguration, timing requirements of the applications must be met. By extension, such requirements are relevant in the design of resource reservations techniques. In this work, we consider such a reconfiguration of the reservation provided by a constant bandwidth server (CBS). Firstly, we de-fine an exact notion of correctness of a server's reconfiguration. Then we design a provably correct server algorithm R-CBS that allows for run-time reconfiguration of a standard CBS. The algorithm maintains specific information about the execution trace and uses it to efficiently perform the reconfiguration at the earliest possible time. We highlight the advantages of R-CBS in comparison to reconfiguration of TDMA servers and in reconfiguring multiple servers simultaneously.
BibTeX:
@inproceedings{Kumar2012,
  author = {Kumar, Pratyush and Stoimenov, Nikolay and Thiele, Lothar},
  title = {An Algorithm for Online Reconfiguration of Resource Reservations for Hard Real--Time Systems},
  booktitle = {Proceedings of the 24th Euromicro Conference on Real--Time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {245--254},
  url = {papers/Kumar2012.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2012.28}
}
Kuo, T.-W. and Li, C.-H. A fixed-priority-driven open environment for real-time applications 1999 Proceedings of the 20th IEEE Real-Time Systems Symposium (RTSS), pp. 256-267  inproceedings DOI URL 
Abstract: This paper extends the useful concept of open systems proposed by W.S. Liu, et al. (1997) in scheduling real-time applications and non-real-time applications, where the schedulability of each real-time application can be validated independently of other applications in the system. We replace the underlying earliest-deadline-first OS scheduler of the open system architecture by W.S. Liu, et al. (1997) with a rate-monotonic OS scheduler. The motivation behind this work is that many existing operating systems may not support the earliest deadline first scheduling very well. We propose to use the idea of sporadic servers to preserve CPU cycles for applications. We also develop schedulability tests for real-time applications which adopt the rate monotonic scheduling algorithm, the earliest deadline first scheduling algorithm, the priority ceiling protocol, and the stack resource policy. We allow tasks in each application to share local and global non-preemptable resources. A global resource synchronization mechanism is proposed. This paper provides a fixed-priority-based alternative for the important open system architecture.
BibTeX:
@inproceedings{Kuo1999,
  author = {Kuo, Tei-Wei and Li, Ching-Hui},
  title = {A fixed-priority-driven open environment for real-time applications},
  booktitle = {Proceedings of the 20th IEEE Real-Time Systems Symposium (RTSS)},
  year = {1999},
  pages = {256--267},
  url = {/papers/Kuo1999.pdf},
  doi = {http://doi.org/10.1109/REAL.1999.818851}
}
Lakshmanan, K., Kato, S. and Rajkumar, R."R. Scheduling Parallel Real--Time Tasks on Multi-core Processors 2010 Proceedings of the 31st IEEE Real--Time Systems Symposium (RTSS), pp. 259-268  inproceedings DOI URL 
Abstract: Massively multi--core processors are rapidly gaining market share with major chip vendors offering an ever increasing number of cores per processor. From a programming perspective, the sequential programming model does not scale very well for such multi-core systems. Parallel programming models such as OpenMP present promising solutions for more effectively using multiple processor cores. In this paper, we study the problem of scheduling periodic real-time tasks on multiprocessors under the fork join structure used in OpenMP. We illustrate the theoretical best-case and worst-case periodic fork-join task sets from a processor utilization perspective. Based on our observations of these task sets, we provide a partitioned preemptive fixed-priority scheduling algorithm for periodic fork-join tasks. The proposed multiprocessor scheduling algorithm is shown to have a resource augmentation bound of 3.42, which implies that any task set that is feasible on m unit speed processors can be scheduled by the proposed algorithm on m processors that are 3:42 times faster.
BibTeX:
@inproceedings{Lakshmanan2010,
  author = {Lakshmanan, Karthik and Kato, Shinpei and Rajkumar, Ragunathan "Raj"},
  title = {Scheduling Parallel Real--Time Tasks on Multi-core Processors},
  booktitle = {Proceedings of the 31st IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {259--268},
  url = {papers/Lakshmanan2010.pdf},
  doi = {http://doi.org/10.1109/RTSS.2010.42}
}
Lakshmanan, K., de Niz, D. and Rajkumar, R."R. Coordinated Task Scheduling, Allocation and Synchronization on Multiprocessors 2009 Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS), pp. 469-478  inproceedings DOI URL 
Abstract: Chip--multiprocessors represent a dominant new shift in the field of processor design. Better utilization of such technology in the real-time context requires coordinated approaches to task allocation, scheduling, and synchronization. In this paper, we characterize various scheduling penalties arising from multiprocessor task synchronization, including (i) blocking delays on global critical sections, (ii) back-to-back execution due to jitter from blocking, and (iii) multiple priority inversions due to remote resource sharing. We analyze the impact of these scheduling penalties under different execution control policies (ECPs) which compensate for the scheduling penalties incurred by tasks due to remote blocking. Subsequently, we develop a synchronization-aware task allocation algorithm for explicitly accommodating these global task synchronization penalties. The key idea of our algorithm is to bundle tasks that access a common shared resource and co-locate them, thereby transforming global resource sharing into local sharing. This approach reduces the above-mentioned penalties associated with remote task synchronization. Experimental results indicate that such a coordinated approach to scheduling, allocation, and synchronization yields significant benefits (as much as 50% savings in terms of required number of processing cores). An implementation of this approach is available as a part of our RT-MAP library1 , which uses the pthreads implementation of Linux-2.6.22.
BibTeX:
@inproceedings{Lakshmanan2009a,
  author = {Lakshmanan, Karthik and de Niz, Dionisio and Rajkumar, Ragunathan "Raj"},
  title = {Coordinated Task Scheduling, Allocation and Synchronization on Multiprocessors},
  booktitle = {Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {469--478},
  url = {papers/Lakshmanan2009a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2009.51}
}
Lakshmanan, K., Rajkumar, R."R. and Lehoczky, J.P. Partitioned Fixed--Priority Preemptive Scheduling for Multi-Core Processors 2009 Proceedings of the 21st Euromicro Conference on Real--time Systems (ECRTS), pp. 239-248  inproceedings URL 
Abstract: Energy and thermal considerations are increasingly driving system designers to adopt multi--core processors. In this paper, we consider the problem of scheduling periodic real-time tasks on multi-core processors using fixed-priority preemptive scheduling. Specifically, we focus on the partitioned (static binding) approach, which statically allocates tasks to processing cores. The well-established 50% bound for partitioned multiprocessor scheduling [10] can be overcome by task-splitting (TS) [19], which allows a task to be split across more than one core. We prove that a utilization bound of 60% per core can be achieved by the partitioned deadline-monotonic scheduling (PDMS) class of algorithms on implicit-deadline tasksets, when the highest-priority task on each processing core is allowed to be split (HPTS). Given the widespread usage of fixed-priority scheduling in commercial real-time and non real-time operating systems (e.g. VxWorks, Linux), establishing such utilization bounds is both relevant and useful. We also show that a specific instance of PDMS HPTS, where tasks are allocated in the decreasing order of size, called PDMS HPTS DS, has a utilization bound of 65% on implicitdeadline task-sets. The PDMS HPTS DS algorithm also achieves a utilization bound of 69% on lightweight implicit-deadline task-sets where no single task utilization exceeds 41.4%. The average-case behavior of PDMS HPTS DS is studied using randomly generated task-sets, and it is seen to have an average schedulable utilization of 88%. We also characterize the overhead of task-splitting using measurements on an Intel Core 2 Duo processor.
BibTeX:
@inproceedings{Lakshmanan2009,
  author = {Lakshmanan, Karthik and Rajkumar, Ragunathan "Raj" and Lehoczky, John P.},
  title = {Partitioned Fixed--Priority Preemptive Scheduling for Multi-Core Processors},
  booktitle = {Proceedings of the 21st Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {239--248},
  url = {papers/Lakshmanan2009.pdf}
}
Lamastra, G., Lipari, G. and Abeni, L. A bandwidth inheritance algorithm for real--time task synchronization in open systems 2001 Proceedings of the 22nd IEEE Real--Time Systems Symposium (RTSS), pp. 151-160  inproceedings DOI URL 
Abstract: In this paper, we present algorithm BandWidth Inheritance (BWI), a new scheduling strategy that extends the bandwidth reservation approach to systems where tasks can interact through shared resources. The proposed algorithm provides temporal isolation between independent groups of tasks, and enables a schedulability analysis for guaranteeing the performance of realtime tasks. After showing that BWI is the natural extension of the well--known Priority Inheritance Protocol to dynamic reservation systems, a formal analysis of the algorithm is presented, and simple guarantee tests for hard real-time tasks are proposed.
BibTeX:
@inproceedings{Lamastra2001,
  author = {Lamastra, Gerardo and Lipari, Giuseppe and Abeni, Luca},
  title = {A bandwidth inheritance algorithm for real--time task synchronization in open systems},
  booktitle = {Proceedings of the 22nd IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2001},
  pages = {151--160},
  url = {papers/Lamastra2001.pdf},
  doi = {http://doi.org/10.1109/REAL.2001.990606}
}
Lassalle, R. Intégration et mesures de performances d'un algorithme d'ordonnancement energétique dans LejosRT 2010 School: ENSTA ParisTech  mastersthesis URL 
Abstract: Le Lego Mindstorms NXT est un jeu de construction et de robotique. Il s’agit d’un petit robot dont les principales caractéristiques sont l’usage d’un processeur 32 bits de type ARM et l’utilisation possible d’une multitude de capteurs différents. De base, ce robot est fourni avec un logiciel de programmation intuitif. En 2006, une petite machine virtuelle du nom de « LeJos » a été portée sur la brique LEGO NXT. Baptisé « LeJos NXJ », cette machine virtuelle offre de nombreux services (langage orienté objet, threads, tableaux, récursivité...) ainsi que les outils nécessaires pour télécharger du code sur le robot NXT. Cependant l’implantation d’une telle machine virtuelle ne permet pas l’utilisation de programme à base de temps réel, caractéristique pourtant essentielle dans la plupart des systèmes embarqués. Lors d’un stage, des étudiants d’une école d’ingénieur ont réussi à implanter sur ce robot une machine virtuelle, baptisé LeJosRT, permettant l’utilisation, en partie, de programmes à base de temps réel. L’objet de ce stage est de reprendre le développement de LejosRT. Il s’agit tout d’abord de créer une documentation et une procédure simplifiée permettant une installation et une utilisation plus aisée de cette machine virtuelle. L’implantation d’un algorithme d’ordonnancement énergétique devra ensuite être réalisée. Pour cela, il sera nécessaire d’implanter, dans un premier temps, des algorithmes de vol de temps creux ou « Slack Stealer » afin de connaître la laxité à tout instant du processeur. L’ajout d’un algorithme de calcul de « charge énergétique » ou « Slack energy » sera effectué dans un deuxième temps. Celui--ci permettra de savoir si, à un instant t, le programme peut continuer sans manquer de ressource énergétique. Enfin, dans un dernier temps, le lien entre les deux algorithmes précédents sera réalisé afin de pouvoir suspendre l’activité du système lors d’un manque d’énergie sans compromettre les échéances des tâches périodiques.
BibTeX:
@mastersthesis{Lassalle2010,
  author = {Lassalle, Rémi},
  title = {Intégration et mesures de performances d'un algorithme d'ordonnancement energétique dans LejosRT},
  school = {ENSTA ParisTech},
  year = {2010},
  url = {papers/Lassalle2010.pdf}
}
Lauzac, S., Melhem, R. and Mossé, D. An Improved Rate--Monotonic Admission Control and Its Applications 2003 IEEE Transactions on Computer
Vol. 52(3), pp. 337-350 
article DOI URL 
Abstract: Rate--monotonic scheduling (RMS) is a widely used real-time scheduling technique. This paper proposes RBound, a new admission control for RMS. RBound has two interesting properties. First, it achieves high processor utilization under certain conditions. We show how to obtain these conditions in a multiprocessor environment and propose a multiprocessor scheduling algorithm that achieves a near optimal processor utilization. Second, the framework developed for RBound remains close to the original RMS framework (that is, task dispatching is still done via a fixed-priority scheme based on the task periods). In particular, we show how RBound can be used to guarantee a timely recovery in the presence of faults and still achieve high processor utilization. We also show how RBound can be used to increase the processor utilization when aperiodic tasks are serviced by a priority exchange server or a deferrable server.
BibTeX:
@article{Lauzac2003,
  author = {Lauzac, Sylvain and Melhem, Rami and Mossé, Daniel},
  title = {An Improved Rate--Monotonic Admission Control and Its Applications},
  journal = {IEEE Transactions on Computer},
  year = {2003},
  volume = {52},
  number = {3},
  pages = {337--350},
  url = {papers/Lauzac2003.pdf},
  doi = {http://doi.org/10.1109/TC.2003.1183947}
}
Lauzac, S., Melhem, R. and Mossé, D. An Efficient RMS Admission Control and its Application to Multiprocessor Scheduling 1998 Proceedings of the 12th International Parallel Processing Symposium (IPPS), pp. 511-518  inproceedings DOI URL 
Abstract: A real--time system must execute functionally correct computations in a timely mannel: In order to guarantee that all tasks accepted in the system will meet their timing requirements, an admission control algorithm must be used to only accept tasks whose requirements can be satisfied. Rate-monotonic scheduling (RMS) is arguably the best known scheduling policy for periodic real-time tasks on uniprocessors. We propose a new and eficient admission control for rate-monotonic scheduling on a uniprocessor and analyze its pelformance. This admission control is then modified to provide an admission control mechanism for multiprocessor systems. Experimental results indicate that this new admission control for multiprocessor systems achieves a processor utilization of up to 96% for a large number of tasks and has a low computational complexity. The proposed admission control is also used to derive a new and better multiprocessor schedulability bound for RMS with provisions for periodic servers and for RMS with tolerance to transient faults.
BibTeX:
@inproceedings{Lauzac1998,
  author = {Lauzac, Sylvain and Melhem, Rami and Mossé, Daniel},
  title = {An Efficient RMS Admission Control and its Application to Multiprocessor Scheduling},
  booktitle = {Proceedings of the 12th International Parallel Processing Symposium (IPPS)},
  publisher = {IEEE Computer Society},
  year = {1998},
  pages = {511--518},
  url = {papers/Lauzac1998.pdf},
  doi = {http://doi.org/10.1109/IPPS.1998.669964}
}
Le Boudec, J.-Y. and Thiran, P. Network Calculus 2001   book URL 
Abstract: Network Calculus is a collection of results based on Min--Plus algebra, which applies to deterministic queuing systems found in communication networks. It can be used for example to understand - the computations for delays used in the IETF guaranteed service - why re-shaping delays can be ignored in shapers or spacer-controllers - a common model for schedulers - deterministic effective bandwidth and much more.
BibTeX:
@book{LeBoudec2001,
  author = {Le Boudec, Jean--Yves and Thiran, Patrick},
  title = {Network Calculus},
  publisher = {Springer--Verlag},
  year = {2001},
  url = {papers/LeBoudec2001.pdf}
}
Lea, D. A Java Fork/Join Framework 2000 Proceedings of the ACM Java Grande Conference, pp. 36-43  inproceedings DOI URL 
Abstract: This paper describes the design, implementation, and performance of a Java framework for supporting a style of parallel programming in which problems are solved by (recursively) splitting them into subtasks that are solved in parallel, waiting for them to complete, and then composing results. The general design is a variant of the work−stealing framework devised for Cilk. The main implementation techniques surround efficient construction and management of tasks queues and worker threads. The measured performance shows good parallel speedups for most programs, but also suggests possible improvements.
BibTeX:
@inproceedings{Lea2000,
  author = {Lea, Doug},
  title = {A Java Fork/Join Framework},
  booktitle = {Proceedings of the ACM Java Grande Conference},
  publisher = {ACM},
  year = {2000},
  pages = {36--43},
  url = {papers/Lea2000.pdf},
  doi = {http://doi.org/10.1145/337449.337465}
}
L'Ecuyer, P. and Buist, E. Simulation in Java with SSJ 2005 Proceedings of the 37th Winter Simulation Conference (WSC), pp. 611-620  inproceedings URL 
Abstract: We describe SSJ, an organized set of software tools offering general--purpose facilities for stochastic simulation programming in Java. It supports the event view, process view, continuous simulation, and arbitrary mixtures of these. Random number generators with multiple streams and substreams, quasi-Monte Carlo methods and their randomizations, and random variate generation for a rich selection of distributions, are all supported in an integrated framework. Performance, flexibility, and extensibility were key criteria in the design and implementation of SSJ. We illustrate its use by simple examples.
BibTeX:
@inproceedings{LEcuyer2005,
  author = {L'Ecuyer, Pierre and Buist, Eric},
  title = {Simulation in Java with SSJ},
  booktitle = {Proceedings of the 37th Winter Simulation Conference (WSC)},
  publisher = {ACM},
  year = {2005},
  pages = {611--620},
  url = {papers/L'Ecuyer2005.pdf}
}
Lee, J. Time--Reversibility of Schedulability Tests 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 294-303  inproceedings DOI URL 
Abstract: For timing guarantees of a set of real--time tasks under a target scheduling algorithm, a number of schedulability tests have been studied. However, there still exist many task sets that are potentially schedulable by a target scheduling algorithm, but proven schedulable by none of existing schedulability tests, especially on a multiprocessor platform. In this paper, we propose a new notion of time-reversibility of schedulability tests, which yields tighter schedulability guarantees by viewing real-time scheduling under a change in the sign of time. To this end, we first define the notion of a time-reversed scheduling algorithm against a target scheduling algorithm; for example, the time-reversed scheduling algorithm against EDF (Earliest Deadline First) is LCFS (Last-Come, First-Served), and the converse also holds. Then, a schedulability test for a scheduling algorithm is said to be time-reversible with respect to schedulability, if all task sets deemed schedulable by the test are also schedulable by its time-reversed scheduling algorithm. To exploit the notion of time-reversibility for tighter schedulability guarantees, we not only prove time-reversibility of an existing schedulability test, but also develop a new time-reversible schedulability test, both of which cover additional schedulable task sets.
Next, we generalize the time--reversibility theory towards partial execution. Utilizing the notion, we can assure the schedulability of a task under a target scheduling algorithm in a divide-and-conquer manner: (i) the first some units of execution guaranteed by a schedulability test for the scheduling algorithm, and (ii) the remaining execution guaranteed by a time-reversible (with respect to partial execution) schedulability test for its time-reversed scheduling algorithm. Such a divide-and-conquer approach has not been directly applied to existing schedulability tests in that they cannot address (ii) effectively. As a case study, this paper develops RTA (Response-Time Analysis) for LCFS, proves its time-reversibility, and applies the divide-and-conquer approach to the test along with an existing EDF schedulability test. Our simulation results show that the time-reversibility theory helps to find up to 13.1% additional EDF-schedulable task sets on a multiprocessor platform.
BibTeX:
@inproceedings{Lee2014a,
  author = {Lee, Jinkyu},
  title = {Time--Reversibility of Schedulability Tests},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {294--303},
  url = {papers/Lee2014a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.18}
}
Lee, J., Easwaran, A. and Shin, I. LLF Schedulability Analysis on Multiprocessor Platforms 2010 Proceedings of the 31st IEEE Real--Time Systems Symposium (RTSS), pp. 25-36  inproceedings DOI URL 
Abstract: LLF (Least Laxity First) scheduling, which assigns a higher priority to a task with smaller laxity, has been known as an optimal preemptive scheduling algorithm on a single processor platform. However, its characteristics upon multiprocessor platforms have been little studied until now. Orthogonally, it has remained open how to efficiently schedule general task systems, including constrained deadline task systems, upon multiprocessors. Recent studies have introduced zero laxity (ZL) policy, which assigns a higher priority to a task with zero laxity, as a promising scheduling approach for such systems (e.g., EDZL). Towards understanding the importance of laxity in multiprocessor scheduling, this paper investigates the characteristics of ZL policy and presents the first ZL schedulability test for any work--conserving scheduling algorithm that employs this policy. It then investigates the characteristics of LLF scheduling, which also employs the ZL policy, and derives the first LLF-specific schedulability test on multiprocessors. It is shown that the proposed LLF test dominates the ZL test as well as the state-of-art EDZL test.
BibTeX:
@inproceedings{Lee2010,
  author = {Lee, Jinkyu and Easwaran, Arvind and Shin, Insik},
  title = {LLF Schedulability Analysis on Multiprocessor Platforms},
  booktitle = {Proceedings of the 31st IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {25--36},
  url = {papers/Lee2010.pdf},
  doi = {http://doi.org/10.1109/RTSS.2010.13}
}
Lee, J., Phan, K., Gu, X., Lee, J., Easwaran, A., Shin, I. and Lee, I. MC--Fluid: Fluid Model-Based Mixed-Criticality Scheduling on Multiprocessors 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 41-52  inproceedings DOI URL 
Abstract: A mixed--criticality system consists of multiple components with different criticalities. While mixed-criticality scheduling has been extensively studied for the uniprocessor case, the problem of efficient scheduling for the multiprocessor case has largely remained open. We design a fluid model-based multiprocessor mixed-criticality scheduling algorithm, called MC-Fluid, in which each task is executed in proportion to its criticality-dependent rate. We propose an exact schedulability condition for MC-Fluid and an optimal assignment algorithm for criticality-dependent execution rates with polynomial complexity. Since MC-Fluid cannot construct a schedule on real hardware platforms due to the fluid assumption, we propose MC-DP-Fair algorithm, which can generate a non-fluid schedule while preserving the same schedulability properties as MC-Fluid. We show that MC-Fluid has a speedup factor of (1 + 5)/2 (≈ 1.618), which is best known in multiprocessor MC scheduling, and simulation results show that MC-DP-Fair outperforms all existing algorithms.
BibTeX:
@inproceedings{Lee2014,
  author = {Lee, Jaewoo and Phan, Kieu--My and, Gu, Xiaozhe and Lee, Jiyeon and Easwaran, Arvind and Shin, Insik and Lee, Insup},
  title = {MC--Fluid: Fluid Model-Based Mixed-Criticality Scheduling on Multiprocessors},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {41--52},
  url = {papers/Lee2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.32}
}
Lee, S.K. On--line Multiprocessor Scheduling Algorithms for Real-Time Tasks 1994
Vol. 2Proceedings of the IEEE Region 10's Ninth Annual International Conference (TENCON), pp. 607-611 
inproceedings URL 
Abstract: The existing on--line scheduling algorithms EDA (Ecrrliest Deadline Algorithm) and LLA (Least Larity Algorithm) are not suficient for scheduling real-time sporadic tasks in multiprocessor systems. EDA has low context switching overhead, but suffers from "multiple processor anomalies." LLA has good scheduling power, but the potential for high contat switching overhead We propose a new on-line scheduling algorithm EDZL which has both good scheduling power and low context switching overhead even in multiprocessor systems.
BibTeX:
@inproceedings{Lee1994,
  author = {Lee, Suk Kyoon},
  title = {On--line Multiprocessor Scheduling Algorithms for Real-Time Tasks},
  booktitle = {Proceedings of the IEEE Region 10's Ninth Annual International Conference (TENCON)},
  publisher = {IEEE Computer Society},
  year = {1994},
  volume = {2},
  pages = {607--611},
  url = {papers/Lee1994.pdf}
}
Lee, Y.-H., Kim, D., Younis, M. and Zhou, J. Scheduling tool and algorithm for integrated modular avionics systems 2000 Proceedings of the 19th Digital Avionics Systems Conference (DASC), pp. 1-8  inproceedings DOI URL 
Abstract: As computer and software technologies have advanced, the approach of Integrated Modular Avionics (IMA) has emerged in the field of avionics systems. The IMA approach can dramatically reduce production and maintenance costs and increase reliability of these safety--critical real time systems. The IMA hardware and foundation software must be able to provide guarantees to the application software so that the real-time constraints of all applications are simultaneously satisfied. In addition, each application must be protected from interference by other applications and the operating system software must itself be protected while physically sharing resources such as processors and communication hardware and busses. In other words, an IMA implementation requires that the concepts of spatial and temporal partitioning are provided and guaranteed. This paper introduces a scheduling tool and its algorithms that can be used to solve the fundamental temporal partitioning problems together with implementation related practical constraints. Based on the two-level scheduling hierarchy architecture of ARINC IMA standards, we model an IMA system composed of multiple partition servers and channel servers. A partition server models a protected application that may be composed of multiple concurrent tasks. A channel server provides temporally and spatially protected message transmission among applications. The ultimate objective of the tool is to provide schedules for both tasks and messages that provide for robust temporal partitioning.
BibTeX:
@inproceedings{Lee2000,
  author = {Lee, Yann--Hang and Kim, Daeyoung and Younis, Mohamed and Zhou, Jeff},
  title = {Scheduling tool and algorithm for integrated modular avionics systems},
  booktitle = {Proceedings of the 19th Digital Avionics Systems Conference (DASC)},
  publisher = {IEEE},
  year = {2000},
  pages = {1--8},
  url = {papers/Lee2000.pdf},
  doi = {http://doi.org/10.1109/DASC.2000.886885}
}
Legout, V., Jan, M. and Pautet, L. An off--line multiprocessor real-time scheduling algorithm to reduce static energy consumption 2013 In proceedings of First Workshop on Highly--Reliable Power-Efficient Embedded Designs (HARSH)  inproceedings DOI URL 
BibTeX:
@inproceedings{Legout2013,
  author = {Legout, Vincent and Jan, Mathieu and Pautet, Laurent},
  title = {An off--line multiprocessor real-time scheduling algorithm to reduce static energy consumption},
  booktitle = {In proceedings of First Workshop on Highly--Reliable Power-Efficient Embedded Designs (HARSH)},
  year = {2013},
  note = {https://github.com/vlegout/yass},
  url = {papers/Legout2013.pdf},
  doi = {http://doi.org/10.1145/2516821.2516839}
}
Lehoczky, J.P. Fixed priority scheduling of periodic task sets with arbitrary deadlines 1990 Proceedings of the 11th IEEE Real--Time Systems Symposium (RTSS), pp. 201-209  inproceedings DOI URL 
Abstract: This paper considers the problem of fixed priority scheduling of periodic tasks with arbitrary deadlines. A general criterion for the schedulability of such a task set is given. Worst case bounds are given which generalize the Liu and Layland bound. The results are shown to provide a basis for developing predictable distributed real--time systems.
BibTeX:
@inproceedings{Lehoczky1990,
  author = {Lehoczky, John P.},
  title = {Fixed priority scheduling of periodic task sets with arbitrary deadlines},
  booktitle = {Proceedings of the 11th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1990},
  pages = {201--209},
  url = {papers/Lehoczky1990.pdf},
  doi = {http://doi.org/10.1109/REAL.1990.128748}
}
Lehoczky, J.P. and Ramos-Thuel, S. An Optimal Algorithm for Scheduling Soft--Aperiodic Tasks in Fixed-Priority Preemptive Systems 1992 Proceedings of the 13th IEEE Real--Time Systems Symposium (RTSS), pp. 110-123  inproceedings URL 
Abstract: This paper presents a new algorithm for servicing soft deadline aperiodic tasks in a real--time system in which hard deadline periodic tasks are scheduled using a fixed priority algorithm. The new algorithm is proved to be optimal in the sense that it provides the shortest aperiodic response time among all possible aperiodic service methods. Simulation studies show that it offers substantial performance improvements over current approaches including the sporadic server algorithm. Moreover, standard queueing formulas can be used to predict aperiodic response times over a wide range of condiiions. The algorithm can be extended to schedule hard deadline aperiodics and to eficiently reclaim unused periodic service time when periodic tasks have stochastic execution times.
BibTeX:
@inproceedings{Lehoczky1992,
  author = {Lehoczky, John P. and Ramos--Thuel, Sandra},
  title = {An Optimal Algorithm for Scheduling Soft--Aperiodic Tasks in Fixed-Priority Preemptive Systems},
  booktitle = {Proceedings of the 13th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1992},
  pages = {110--123},
  url = {papers/Lehoczky1992.pdf}
}
Lehoczky, J.P., Sha, L. and Ding, Y. The Rate Monotonic Scheduling Algorithm: Exact Characterization And Average Case Behavior 1989 Proceedings of the 10th IEEE Real--Time Systems Symposium (RTSS), pp. 166-171  inproceedings URL 
Abstract: This paper presents an exact characterization of the ability of the rate monotonic scheduling algorithm to meet the deadlines of a periodic task set. In addition, a stochastic analysis is presented which gives the probability distribution of the breakdown utilization of randomly generated task sets. It is shown that as the task set size increases, the task computation times become of little importance, and the breakdown utilization converges to a constant determined by the task periods. For uniformly distributed tasks, a breakdown utilization of 88% is a reasonable characterization of the breakdown utilization level. An interesting case is presented in which the average case breakdown utilization reaches the worst case Liu and Layland lower bound.
BibTeX:
@inproceedings{Lehoczky1989,
  author = {Lehoczky, Jonh P. and Sha, Lui and Ding, Ye},
  title = {The Rate Monotonic Scheduling Algorithm: Exact Characterization And Average Case Behavior},
  booktitle = {Proceedings of the 10th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1989},
  pages = {166--171},
  url = {papers/Lehoczky1989.pdf}
}
Lemerre, M., David, V., Aussaguès, C. and Vidal-Naquet, G. An Introduction to Time--Constrained Automata 2010
Vol. 38Proceedings of the 3rd Workshop on Interaction and Concurrency Experience (ICE), pp. 83-98 
inproceedings DOI URL 
Abstract: We present time--constrained automata (TCA), a model for hard real-time computation in which agents behaviors are modeled by automata and constrained by time intervals. TCA actions can have multiple start time and deadlines, can be aperiodic, and are selected dynamically following a graph, the time-constrained automaton. This allows expressing much more precise time constraints than classical periodic or sporadic model, while preserving the ease of scheduling and analysis. We provide some properties of this model as well as their scheduling semantics. We show that TCA can be automatically derived from source-code, and optimally scheduled on single processors using a variant of EDF. We explain how time constraints can be used to guarantee communication determinism by construction, and to study when possible agent interactions happen.
BibTeX:
@inproceedings{Lemerre2010,
  author = {Lemerre, Matthieu and David, Vincent and Aussaguès, Christophe and Vidal--Naquet, Guy},
  title = {An Introduction to Time--Constrained Automata},
  booktitle = {Proceedings of the 3rd Workshop on Interaction and Concurrency Experience (ICE)},
  year = {2010},
  volume = {38},
  pages = {83--98},
  url = {papers/Lemerre2010.pdf},
  doi = {http://doi.org/10.4204/EPTCS.38.9}
}
Lemerre, M., David, V., Aussaguès, C. and Vidal-Naquet, G. Equivalence between Schedule Representations: Theory and Applications 2008 Proceedings of the 14th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS), pp. 237-247  inproceedings DOI URL 
Abstract: Multiprocessor scheduling problems are hard because of the numerous constraints on valid schedules to take into account. This paper presents new schedule representations in order to overcome these difficulties, by allowing processors to be fractionally allocated. We prove that these representations are equivalent to the standard representations when preemptive scheduling is allowed. This allows the creation of scheduling algorithms and the study of feasibility in the simpler representations. We apply this method throughout the paper. Then, we use it to provide new simple solutions to the previously solved implicit--deadline periodic scheduling problem. We also tackle the more general problem of scheduling arbitrary time-triggered tasks, and thus in particular solve the open multiprocessor general periodic tasks scheduling problem. Contrary to previous solutions like the PFair class of algorithms, the proposed solution also works when processors have different speeds. We complete the method by providing an online schedule transformation algorithm, that allows the efficient handling of both time-triggered and event-triggered tasks, as well as the creation of online rate-based scheduling algorithms on multiprocessors.
BibTeX:
@inproceedings{Lemerre2008,
  author = {Lemerre, Matthieu and David, Vincent and Aussaguès, Christophe and Vidal--Naquet, Guy},
  title = {Equivalence between Schedule Representations: Theory and Applications},
  booktitle = {Proceedings of the 14th IEEE Real--Time and Embedded Technology and Applications Symposium (RTAS)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {237--247},
  url = {papers/Lemerre2008.pdf},
  doi = {http://doi.org/10.1109/RTAS.2008.17}
}
Lemerre, M., David, V., Aussaguès, C. and Vidal-Naquet, G. A new representation for the scheduling problem and its applications 2006 Proceeding of the Work--in-Progress Session of the 27th IEEE Real-Time Systems Symposium (WiP RTSS), pp. 89-92  inproceedings URL 
Abstract: We present a new representation for the scheduling problem that allows a significant simplication of its solving, especially for the multiprocessor case. We use this representation to solve in an efficient way the periodic scheduling problem on uniform multiprocessors, which has been open for a long time. We also derive optimal multiprocessor schedulers for several other important cases, such as finite job sets and real--time OASIS task systems.
BibTeX:
@inproceedings{Lemerre2006,
  author = {Lemerre, Matthieu and David, Vincent and Aussaguès, Christophe and Vidal--Naquet, Guy},
  title = {A new representation for the scheduling problem and its applications},
  booktitle = {Proceeding of the Work--in-Progress Session of the 27th IEEE Real-Time Systems Symposium (WiP RTSS)},
  year = {2006},
  pages = {89--92},
  url = {papers/Lemerre2006.pdf}
}
Lemerre, M. and Ohayon, E. A model of parallel deterministic real--time computation 2012 Proceedings of the 33rd IEEE Real--Time Systems Symposium (RTSS), pp. 273-282  inproceedings DOI URL 
Abstract: This paper presents a model of computation based on real--time constraints and asynchronous message passing, and proves a sufficient and necessary condition for this model to be deterministic. The model is then extended with deterministic error handling, meaning that the same error yields the same consequences on the system. We consider two different error occurrence models: at a specific time, or at a specific instruction, and conclude that the “error at a specific time” model is more suitable for practical use. We proceed by presenting a concrete implementation of this model in the PharOS real-time system.
BibTeX:
@inproceedings{Lemerre2012,
  author = {Lemerre, Mathieu and Ohayon, Emmanuel},
  title = {A model of parallel deterministic real--time computation},
  booktitle = {Proceedings of the 33rd IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {273--282},
  url = {papers/Lemerre2012.pdf},
  doi = {http://doi.org/10.1109/RTSS.2012.78}
}
Lemerre, M., Ohayon, E., Chabrol, D., Jan, M. and Jacques, M.-B. Method and Tools for Mixed--Criticality Real-Time Applications within PharOS 2011 Proceedings of the 14th IEEE International Symposium on Object/Component/Service--Oriented Real-Time Distributed Computing Workshops (ISORC), pp. 41-48  inproceedings DOI URL 
Abstract: This paper provides an overview of some principles and mechanisms to securely operate mixed--criticality real-time systems on embedded platforms. Those principles are illustrated with PharOS a complete set of tools to design, implement and execute real-time systems on automotive embedded platforms. The keystone of this approach is a dynamic time-triggered methodology that supports full temporal isolation without wasting CPU time. In addition, memory isolation is handled through automatic off-line generation of fine-grained memory protection tables used at runtime. These isolation mechanisms are building blocks for the support of mixed-criticality applications. Several extensions have been brought to this model to expand the support for mixed-criticality within the system. These extensions feature fault recovery, support for the cohabitation of event-triggered with time-triggered tasks and paravirtualization of other operating systems. The contribution of this paper is to provide a high-level description of these extensions, along with an analysis of their impact on the global system safety, in particular on the determinism property of the PharOS model.
BibTeX:
@inproceedings{Lemerre2011,
  author = {Lemerre, Matthieu and Ohayon, Emmanuel and Chabrol, Damien and Jan, Mathieu and Jacques, Marie--Bénédicte},
  title = {Method and Tools for Mixed--Criticality Real-Time Applications within PharOS},
  booktitle = {Proceedings of the 14th IEEE International Symposium on Object/Component/Service--Oriented Real-Time Distributed Computing Workshops (ISORC)},
  publisher = {IEEE Computer Society},
  year = {2011},
  pages = {41--48},
  url = {papers/Lemerre2011.pdf},
  doi = {http://doi.org/10.1109/ISORCW.2011.15}
}
Leng, Q., Wei, Y., Han, S., Mok, A.K.-L., Zhang, W. and Tomizuka, M. Improving Control Performance by Minimizing Jitter in RT--WiFi Networks 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 63-73  inproceedings DOI URL 
Abstract: Wireless networked control systems have received significant attention due to their great advantages in enhanced system mobility, and reduced deployment and maintenance cost. To support a wide range of high--speed wireless control applications, we presented in our prior work the design and implementation of a flexible real-time high-speed wireless communication platform called RT-WiFi. RT-WiFi currently provides up to 6kHz sampling rate and deterministic timing guarantee on packet delivery. While guaranteed delivery latency is essential for networked control, control performance is also impacted by communication jitter and other QoS parameters. To reduce jitter, a flexible network manager is needed to control network-wide scheduling of packet transportation. In this paper, we present an RT-WiFi network manager design and propose efficient solutions for two fundamental RT-WiFi network management problems. To improve control performance in networked control systems, our RT-WiFi network manager is designed to generate data link layer communication schedule with minimum jitter under both static and dynamic network topologies. In order to minimize network management overhead, an efficient data structure called S-tree is invented to manage the communication requests to deal with network dynamics. We have implemented the RT-WiFi network manager, and validated its network and control performance through extensive experiments with a real application.
BibTeX:
@inproceedings{Leng2014,
  author = {Leng, Quan and Wei, Yi--Hung and Han, Song and Mok, Aloysius Ka-Lau and Zhang, Wenlong and Tomizuka, Masayoshi},
  title = {Improving Control Performance by Minimizing Jitter in RT--WiFi Networks},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {63--73},
  url = {papers/Leng2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.26}
}
Lenstra, J.K., Shmoys, D.B. and Tardos, É. Approximation algorithms for scheduling unrelated parallel machines 1990 Mathematical Programming
Vol. 46(1), pp. 259-271 
article DOI URL 
BibTeX:
@article{Lenstra1990,
  author = {Lenstra, Jan Karel and Shmoys, David B. and Tardos, Éva},
  title = {Approximation algorithms for scheduling unrelated parallel machines},
  journal = {Mathematical Programming},
  year = {1990},
  volume = {46},
  number = {1},
  pages = {259--271},
  url = {papers/Lenstra1990.pdf},
  doi = {http://doi.org/10.1007/BF01585745}
}
Leontyev, H. and Anderson, J.H. Generalized tardiness bounds for global multiprocessor scheduling 2010 Real--Time Systems
Vol. 44(1-3), pp. 26-71 
article DOI URL 
Abstract: We consider the issue of deadline tardiness under global multiprocessor scheduling algorithms. We present a general tardiness--bound derivation that is applicable to a wide variety of such algorithms (including some whose tardiness behavior has not been analyzed before). Our derivation is very general: job priorities may change rather arbitrarily at runtime, capacity restrictions may exist on certain processors, and, under certain conditions, non-preemptive regions are allowed. Our results show that, with the exception of static-priority algorithms, most global algorithms considered previously have bounded tardiness. In addition, our results provide a simple means for checking whether tardiness is bounded under newly-developed algorithms.
BibTeX:
@article{Leontyev2010,
  author = {Leontyev, Hennadiy and Anderson, James H.},
  title = {Generalized tardiness bounds for global multiprocessor scheduling},
  journal = {Real--Time Systems},
  publisher = {Springer Netherlands},
  year = {2010},
  volume = {44},
  number = {1--3},
  pages = {26--71},
  note = {10.1007/s11241--009-9089-2},
  url = {papers/Leontyev2010.pdf},
  doi = {http://doi.org/10.1007/s11241--009-9089-2}
}
Leung, J.Y.-T. A New Algorithm for Scheduling Periodic Real--Time Tasks 1989 Algorithmica
Vol. 4(1-4), pp. 209-219 
article DOI URL 
Abstract: We consider the problem of preemptively scheduling a set of periodic, real--time tasks on a multiprocessor computer system. We give a new scheduling algorithm, the so-called Slack-Time Algorithm, and show that it is more effective than the known Deadline Algorithm. We also give an (exponential-time) algorithm to decide if a task system is schedulable by the Slack-Time or the Deadline Algorithm. The same algorithm can also be used to decide if a task system is schedulable by any given fixed-priority scheduling algorithm. This resolves an open question posed by Leung and Whitehead. Finally, it is shown that the problem of deciding if a task system is schedulable by the Slack-Time, the Deadline, or any given fixed-priority scheduling algorithm is co-NP-hard for each fixed m≥1.
BibTeX:
@article{Leung1989,
  author = {Leung, Joseph Yuk--Tong},
  title = {A New Algorithm for Scheduling Periodic Real--Time Tasks},
  journal = {Algorithmica},
  year = {1989},
  volume = {4},
  number = {1--4},
  pages = {209--219},
  url = {papers/Leung1989.pdf},
  doi = {http://doi.org/10.1007/BF01553887}
}
Leung, J.Y.-T. and Whitehead, J. On the Complexity of Fixed--Priority Scheduling of Periodic, Real-Time Tasks 1982 Performance Evaluation
Vol. 2(4), pp. 237-250 
article DOI URL 
Abstract: We consider the complexity of determining whether a set of periodic, real--time tasks can be scheduled on m greater-or-equal, slanted 1 identical processors with respect to fixed-priority scheduling. It is shown that the problem is NP-hard in all but one special case. The complexity of optimal fixed-priority scheduling algorithm is also discussed.
BibTeX:
@article{Leung1982,
  author = {Leung, Joseph Yuk--Tong and Whitehead, Jennifer},
  title = {On the Complexity of Fixed--Priority Scheduling of Periodic, Real-Time Tasks},
  journal = {Performance Evaluation},
  year = {1982},
  volume = {2},
  number = {4},
  pages = {237--250},
  url = {papers/Leung1982.pdf},
  doi = {http://doi.org/10.1016/0166-5316(82)90024-4}
}
Levin, G., Funk, S.H., Pye, I. and Brandt, S. DP--Fair: A Simple Model for Understanding Optimal Multiprocessor Scheduling 2010 Proceedings of the 22nd Euromicro Conference on Real--time Systems (ECRTS), pp. 3-13  inproceedings DOI URL 
Abstract: We consider the problem of optimal real--time scheduling of periodic and sporadic tasks for identical multiprocessors. A number of recent papers have used the notions of fluid scheduling and deadline partitioning to guarantee optimality and improve performance. In this paper, we develop a unifying theory with the DP-Fair scheduling policy and examine how it overcomes problems faced by greedy scheduling algorithms. We then present a simple DP-Fair scheduling algorithm, DP-Wrap, which serves as a least common ancestor to many recent algorithms. We also show how to extend DP-Fair to the scheduling of sporadic tasks with arbitrary deadlines.
BibTeX:
@inproceedings{Levin2010,
  author = {Levin, Greg and Funk, Shelby Hyatt and Pye, Ian and Brandt, Scott},
  title = {DP--Fair: A Simple Model for Understanding Optimal Multiprocessor Scheduling},
  booktitle = {Proceedings of the 22nd Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {3--13},
  url = {papers/Levin2010.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2010.34}
}
Li, H. and Baruah, S.K. Global Mixed--Criticality Scheduling on Multiprocessors 2012 Proceedings of the 24th Euromicro Conference on Real--Time Systems (ECRTS), pp. 166-175  inproceedings DOI URL 
Abstract: The scheduling of mixed--criticality implicit-deadline sporadic task systems on identical multiprocessor platforms is considered, when inter-processor migration is permitted. A scheduling algorithm is derived and proved correct, and its properties investigated. Theoretical analysis (in the form of both a speedup factor and sufficient schedulability conditions) as well as extensive simulation experiments serve to demonstrate its effectiveness.
BibTeX:
@inproceedings{Li2012a,
  author = {Li, Hoahan and Baruah, Sanjoy K.},
  title = {Global Mixed--Criticality Scheduling on Multiprocessors},
  booktitle = {Proceedings of the 24th Euromicro Conference on Real--Time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {166--175},
  url = {papers/Li2012a.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2012.41}
}
Li, J., Agrawal, K., Lu, C. and Gill, C. Analysis of Global EDF for Parallel Tasks 2013 Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS)  inproceedings  
Abstract: As multicore processors become ever more prevalent, it is important for real--time programs to take advantage of intra-task parallelism in order to support computation-intensive applications with tight deadlines. We prove that a Global Earliest Deadline First (GEDF) scheduling policy provides a capacity augmentation bound of 4-2/m and a resource augmentation bound of 2-1/m for parallel tasks in the general directed acyclic graph model. For the proposed capacity augmentation bound of 4-2/m for implicit deadline tasks under GEDF, we prove that if a task set has a total utilization of at most m/(4-2/m) and each task’s critical path length is no more than 1/(4-2/m) of its deadline, it can be scheduled on a machine with m processors under GEDF. Our capacity augmentation bound therefore can be used as a straightforward schedulability test. For the standard resource augmentation bound of 2-1/m for arbitrary deadline tasks under GEDF, we prove that if an ideal optimal scheduler can schedule a task set on m unit-speed processors, then GEDF can schedule the same task set on m processors of speed 2-1/m. However, this bound does not lead to a schedulabilty test since the ideal optimal scheduler is only hypothetical and is not known. Simulations confirm that the GEDF is not only safe under the capacity augmentation bound for various randomly generated task sets, but also performs surprisingly well and usually outperforms an existing scheduling technique that involves task decomposition.
BibTeX:
@inproceedings{Li2013,
  author = {Li, Jing and Agrawal, Kunal and Lu, Chenyang and Gill, Christopher},
  title = {Analysis of Global EDF for Parallel Tasks},
  booktitle = {Proceedings of the 25th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2013},
  note = {To appear}
}
Li, J., Qiu, M., Niu, J.-W., Yang, L.T., Zhu, Y. and Ming, Z. Thermal--Aware Task Scheduling in 3D Chip Multiprocessor with Real-Time Constrained Workloads 2013 ACM Transactions on Embedded Computing Systems (TECS)
Vol. 12(2) 
article DOI URL 
Abstract: Chip multiprocessor (CMP) techniques have been implemented in embedded systems due to tremendous computation requirements. Three--dimension (3D) CMP architecture has been studied recently for integrating more functionalities and providing higher performance. The high temperature on chip is a critical issue for the 3D architecture. In this article, we propose an online thermal prediction model for 3D chips. Using this model, we propose novel task scheduling algorithms based on rotation scheduling to reduce the peak temperature on chip. We consider data dependencies, especially inter-iteration dependencies that are not well considered in most of the current thermal-aware task scheduling algorithms. Our simulation results show that our algorithms can efficiently reduce the peak temperature up to 8.1°C.
BibTeX:
@article{Li2013a,
  author = {Li, Jiayin and Qiu, Meikang and Niu, Jian--Wei and Yang, Laurence T. and Zhu, Yongxin and Ming, Zhong},
  title = {Thermal--Aware Task Scheduling in 3D Chip Multiprocessor with Real-Time Constrained Workloads},
  journal = {ACM Transactions on Embedded Computing Systems (TECS)},
  year = {2013},
  volume = {12},
  number = {2},
  url = {papers/Li2013a.pdf},
  doi = {http://doi.org/10.1145/2423636.2423642}
}
Li, X., Cros, O. and George, L. The Trajectory approach for AFDX FIFO networks revisited and corrected 2014 Proceedings of the 20th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)  inproceedings  
Abstract: We consider the problem of dimensioning real-- time AFDX FIFO networks with a worst-case end-to-end delay analysis. The state-of-the-art has considered several approaches to compute these worst-case end-to-end delays. Among them, the Trajectory approach has received more attention as it has been shown to provide tight end-to-end delay upper bounds. Recently, it has been proved that current Trajectory analysis can be optimistic for some corner cases, leading in its current form, to certification issues. In this paper, we first characterize the source of optimism in the Trajectory approach on detailed examples. Then, we provide a correction to the identified problems. Two problems are solved: the first one is on the definition of the time interval to consider for the worst-case end-to-end response time computation of flows at their source nodes. The second one is on the way that serialized frames are taken into account in the worst-case delay analysis.
BibTeX:
@inproceedings{Li2014,
  author = {Li, Xiaoting and Cros, Olivier and George, Laurent},
  title = {The Trajectory approach for AFDX FIFO networks revisited and corrected},
  booktitle = {Proceedings of the 20th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2014}
}
Li, X., Schabarg, J.-L. and Fraboul, C. Worst--case delay analysis on a real-time heterogeneous network 2012 Proceedings of the 7th IEEE Internation Symposium on Industrial Embedded Systems (SIES), pp. 11-20  inproceedings DOI URL 
Abstract: A heterogeneous network, where a switched Ethernet backbone interconnects several existing CAN buses via bridges, is a promising candidate to build a large scale network. For real--time applications, deterministic communication is a key issue. A worst-case delay analysis on such a network has to deal with heterogeneity properties, such as different bandwidths, scheduling policies and bridging strategies. In this paper, two approaches are proposed. The first one is based on a hierarchical component-based approach. The second one is an adapted Trajectory approach which integrates heterogeneity properties. Moreover, pessimism introduced by the adapted Trajectory approach is analyzed and an optimization of this approach is proposed.
BibTeX:
@inproceedings{Li2012b,
  author = {Li, Xiaoting and Schabarg, Jean--Luc and Fraboul, Christian},
  title = {Worst--case delay analysis on a real-time heterogeneous network},
  booktitle = {Proceedings of the 7th IEEE Internation Symposium on Industrial Embedded Systems (SIES)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {11--20},
  url = {papers/Li2012b.pdf},
  doi = {http://doi.org/10.1109/SIES.2012.6356565}
}
Li, Y., Cheng, A.M. and Mok, A.K.-L. Regularity--Based Partitioning of Uniform Resources in Real-Time Systems 2012 Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 368-377  inproceedings DOI URL 
Abstract: Hierarchical scheduling is a hot topic in real time systems. In a hierarchical real--time system, the resource partition is the intermediate level between physical resources and real-time tasks. A resource partition operates on the shared physical resources at a fraction of the rate, and serves as a scheduling interface between the lower-level real-time tasks and the shared physical resources. Thus a key problem is how to define this scheduling interface on resource partitions. Regularity-bounded methodology is one important type of resource partitioning algorithms. This paper extends Mok and Feng's Regularity-based Resource Partition Model from a single-resource platform to a uniform multiresource platform. We present a resource partitioning algorithm called AAF Multi Scheduling for solving the time slice overlap problem on a multiresource platform without violating the schedulability bound given by Feng on a single-resource platform. AAF Multi is a global scheduling algorithm with O(OMEGA * Log OMEGA) time complexity (OMEGA = resource amount * hyper period), where hyper period is the least common multiple of the periods of the resource partitions.
BibTeX:
@inproceedings{Li2012,
  author = {Li, Yu and Cheng, Albert M.K. and Mok, Aloysius Ka--Lau},
  title = {Regularity--Based Partitioning of Uniform Resources in Real-Time Systems},
  booktitle = {Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {368--377},
  url = {papers/Li2012.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2012.40}
}
Li, Y., West, R., Cheng, Z. and Missimer, E.S. Predictable Communication and Migration in the Quest--V Separation Kernel: 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 272-283  inproceedings DOI URL 
Abstract: Quest--V is a separation kernel, which partitions a system into a collection of sandboxes. Each sandbox encapsulates one or more processing cores, a region of machine physical memory, and a subset of I/O devices. Quest-V behaves like a distributed system on a chip, using explicit communication channels to exchange data and migrate addresses spaces between sandboxes, which operate like traditional hosts. This design has benefits in safety-critical systems, which require continued availability in the presence of failures. Additionally, online faults can be recovered without rebooting an entire system. However, the programming model for such a system is more complicated. Each sandbox has its own local scheduler, and threads must communicate using message passing with those in remote sandboxes. Similarly, address spaces may need to be migrated between sandboxes, to ensure newly forked processes do not violate the feasibility of existing local task schedules. Migration may also be needed to move a thread closer to its required resources, such as I/O devices that are not directly available in the local sandbox. This paper describes how Quest-V performs real-time communication and migration without violating service guarantees for existing threads.
BibTeX:
@inproceedings{Li2014a,
  author = {Li, Ye and West, Richard and Cheng, Zhuogun and Missimer, Eric S.},
  title = {Predictable Communication and Migration in the Quest--V Separation Kernel:},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {272--283},
  url = {papers/Li2014a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.17}
}
Lipari, G. and Bini, E. A Framework for Hierarchical Scheduling on Multiprocessors: From Application Requirements to Run-Time Allocation 2010 Proceedings of the 31st IEEE Real-Time Systems Symposium (RTSS), pp. 249-258  inproceedings DOI URL 
Abstract: Hierarchical scheduling is a promising methodology for designing and deploying real-time applications, since it enables component-based design and analysis, and supports temporal isolation among competing applications. In hierarchical scheduling an application is described by means of a temporal interface. The designer faces the problem of how to derive the interface parameters so to make the application schedulable, at the same time minimizing the waste of computational resources. The problem is particularly relevant in multiprocessor systems, where it is not clear yet how the interface parameters influence the schedulability of the application and allocation on the physical platform. In this paper we present three novel contributions to hierarchical scheduling for multiprocessor systems. First, we propose the Bounded-Delay Multipartition (BDM), a new interface specification model that allows the designer to balance resource usage versus flexibility in selecting the virtual platform parameters. Second, we explore the schedulability region of a real-time application on top of a generic virtual platform, and derive the interface parameter. Finally, we propose Fluid Best-Fit, an algorithm that takes advantage of the extra degree of flexibility provided by the BDM to compute the virtual platform parameters and allocate it on the physical platform. The performance of the algorithm is evaluated by simulations.
BibTeX:
@inproceedings{Lipari2010,
  author = {Lipari, Giuseppe and Bini, Enrico},
  title = {A Framework for Hierarchical Scheduling on Multiprocessors: From Application Requirements to Run-Time Allocation},
  booktitle = {Proceedings of the 31st IEEE Real-Time Systems Symposium (RTSS)},
  year = {2010},
  pages = {249--258},
  url = {/papers/Lipari2010.pdf},
  doi = {http://doi.org/10.1109/RTSS.2010.1}
}
Lipari, G. and Bini, E. Resource partitioning among real-time applications 2003 Proceedings of the 15th Euromicro Conference on Real-Time Systems (ECRTS), pp. 151-158  inproceedings DOI URL 
Abstract: When executing different real-time applications on a single processor system, one problem is how to compose these applications and guarantee at the same time that their timing requirements are not violated. A possible way of composing applications is through the resource reservation approach. Each application is handled by a dedicated server that is assigned a fraction of the processor. Using this approach, the system can be seen as a two-level hierarchical scheduler. A considerable amount of work has been recently addressed to the analysis of this kind of hierarchical systems. However, a question is still unanswered: given a set of real-time tasks to be handled by a server, how to assign the server parameters so that the task set is feasible? In this paper, we answer to the previous question for the case of fixed priority local scheduler by presenting a methodology for computing the class of server parameters that make the task set feasible.
BibTeX:
@inproceedings{Lipari2003,
  author = {Lipari, Giuseppe and Bini, Enrico},
  title = {Resource partitioning among real-time applications},
  booktitle = {Proceedings of the 15th Euromicro Conference on Real-Time Systems (ECRTS)},
  year = {2003},
  pages = {151--158},
  url = {/papers/Lipari2003.pdf},
  doi = {http://doi.org/10.1109/EMRTS.2003.1212738}
}
Liu, C. and Chen, J.-J. Bursty--Interference Analysis Techniques for Analyzing Complex Real-Time Task Models 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 173-183  inproceedings DOI URL 
Abstract: Due to the recent trend towards building complex real--time cyber-physical systems, system designers need to develop and choose expressive formal models for representing such systems, as the model should be adequately expressive such that it can accurately convey the relevant characteristics of the system being modeled. Compared to the classical sporadic task model, there exist a number of real-time task models that are more expressive. However, such models are often complex and thus are rather difficult to be analyzed efficiently. Due to this reason, prior analysis methods for dealing with such complex task models are pessimistic. In this paper, a novel analysis technique, namely the bursty-interference analysis, is presented for analyzing two common expressive real-time task models, the general self-suspending task model and the deferrable server task model. This technique is used to derive new uniprocessor utilization-based schedulability tests and rate-monotonic utilization bounds for the two considered task models scheduled under rate-monotonic scheduling. Extensive experiments presented herein show that our proposed tests improve upon prior tests in all scenarios, in many cases by a wide margin. To the best of our knowledge, these are the first techniques that can efficiently analyze the general self-suspending and deferrable server task models on uniprocessors.
BibTeX:
@inproceedings{Liu2014,
  author = {Liu, Cong and Chen, Jian--Jia},
  title = {Bursty--Interference Analysis Techniques for Analyzing Complex Real-Time Task Models},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {173--183},
  url = {papers/Liu2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.10}
}
Liu, C.L. and Layland, J.W. Scheduling Algorithms for Multiprogramming in a Hard--Real-Time Environment 1973 Journal of the ACM
Vol. 20(1), pp. 46-61 
article DOI URL 
Abstract: The problem of multiprogram scheduling on a single processor is studied from the viewpoint of the characteristics peculiar to the program functions that need guaranteed service. It is shown that an optimum fixed priority scheduler possesses an upper bound to processor utilization which may be as low as 70 percent for large task sets. It is also shown that full processor utilization can be achieved by dynamically assigning priorities on the basis of their current deadlines. A combination of these two scheduling techniques is also discussed.
BibTeX:
@article{Liu1973,
  author = {Liu, Chung Laung and Layland, James W.},
  title = {Scheduling Algorithms for Multiprogramming in a Hard--Real-Time Environment},
  journal = {Journal of the ACM},
  year = {1973},
  volume = {20},
  number = {1},
  pages = {46--61},
  url = {papers/Liu1973.pdf},
  doi = {http://doi.org/10.1145/321738.321743}
}
Liu, R., Mills, A.F. and Anderson, J.H. Independence Thresholds: Balancing Tractability and Practicality in Soft Real--Time Stochastic Analysis 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 314-323  inproceedings DOI URL 
Abstract: The issue of stochastic response--time analysis is considered in the context of soft real-time multiprocessor schedulers. For such analysis to yield tractable, closed-form results, it is inevitably necessary to assume that execution times are probabilistically independent. However, stochastic dependencies among tasks are often common in actual systems. To enable closed-form analysis results to be applied to such systems, the concept of an independence threshold is introduced. Such a threshold is a “tunable” per-task parameter that can be adjusted to control the extent of dependency in task execution times as assumed in analysis; such thresholds can even be applied in settings where explicit dependencies exist among tasks through resource sharing. A method is presented for setting independence thresholds in which measured task execution times are subjected to known statistical independence tests. This method is applied in a case study involving MPEG decoding. In this case study, the usage of independence thresholds enabled up to a 3.5-fold reduction in provisioned task execution times compared to a worst-case provisioning without compromising analysis assumptions.
BibTeX:
@inproceedings{Liu2014a,
  author = {Liu, Rui and Mills, Alex F. and Anderson, James H.},
  title = {Independence Thresholds: Balancing Tractability and Practicality in Soft Real--Time Stochastic Analysis},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {314--323},
  url = {papers/Liu2014a.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.38}
}
Liu, X., Cao Jiannong, Tang, S. and Wen, J. Wi--Sleep: Contactless Sleep Monitoring via WiFi Signals 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 346-355  inproceedings DOI URL 
Abstract: Is it possible to leverage WiFi signals collected in bedrooms to monitor a person’s sleep? In this paper, we show that with off--the-shelf WiFi devices, fine-grained sleep information like a person’s respiration, sleeping postures and rollovers can be successfully extracted. We do this by introducing Wi-Sleep, the first sleep monitoring system based on WiFi signals. Wi-Sleep adopts off-the-shelf WiFi devices to continuously collect the fine-grained wireless channel state information (CSI) around a person. From the CSI, Wi-Sleep extracts rhythmic patterns associated with respiration and abrupt changes due to the body movement. Compared to existing sleep monitoring systems that usually require special devices attached to human body (i.e. probes, head belt, and wrist band), Wi-Sleep is completely contactless. In addition, different from many vision-based sleep monitoring systems, Wi-Sleep is robust to low-light environments and does not raise privacy concerns. Preliminary testing results show that the Wi-Sleep can reliably track a person’s respiration and sleeping postures in different conditions.
BibTeX:
@inproceedings{Liu2014b,
  author = {Liu, Xuefeng and Cao, Jiannong, and Tang, Shaojie and Wen, Jiaqi},
  title = {Wi--Sleep: Contactless Sleep Monitoring via WiFi Signals},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {346--355},
  url = {papers/Liu2014b.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.30}
}
López, J.M., Díaz, J.L. and García, D.F. Minimum and Maximum Utilization Bounds for Multiprocessor Rate Monotonic Scheduling 2004 IEEE Transactions on Parallel and Distributed Systems
Vol. 15(7), pp. 642-653 
article DOI URL 
Abstract: The utilization bound for real--time Rate Monotonic (RM) scheduling on uniprocessors is extended to multiprocessors with partitioning-based scheduling. This allows fast schedulability tests to be performed on multiprocessors and quantifies the influence of key parameters, such as the number of processors and task sizes on the schedulability of the system. The multiprocessor utilization bound is a function of the allocation algorithm, so among all the allocation algorithms there exists at least one allocation algorithm providing the minimum multiprocessor utilization bound, and one allocation algorithm providing the maximum multiprocessor utilization bound. We prove that the multiprocessor utilization bound associated with the allocation heuristic Worst Fit (WF) coincides with that minimum if we use Liu and Layland’s bound (LLB) as the uniprocessor schedulability condition. In addition, we present a class of allocation algorithms sharing the same multiprocessor utilization bound which coincides with the aforementioned maximum using LLB. The heuristics First Fit Decreasing (FFD) and Best Fit Decreasing (BFD) belong to this class. Thus, not even an optimal allocation algorithm can guarantee a higher multiprocessor utilization bound than that of FFD and BFD using LLB. Finally, the pessimism of the multiprocessor utilization bounds is estimated through extensive simulations.
BibTeX:
@article{Lopez2004,
  author = {López, José M. and Díaz, José L. and García, Daniel F.},
  title = {Minimum and Maximum Utilization Bounds for Multiprocessor Rate Monotonic Scheduling},
  journal = {IEEE Transactions on Parallel and Distributed Systems},
  year = {2004},
  volume = {15},
  number = {7},
  pages = {642--653},
  url = {papers/Lopez2004.pdf},
  doi = {http://doi.org/10.1109/TPDS.2004.25}
}
López, J.M., Díaz, J.L. and García, D.F. Utilization Bounds for EDF Scheduling on Real--Time Multiprocessor Systems 2004 Real--Time Systems
Vol. 28(1), pp. 39-68 
article DOI URL 
Abstract: The utilization bound for earliest deadline first (EDF) scheduling is extended from uniprocessors to homogeneous multiprocessor systems with partitioning strategies. First results are provided for a basic task model, which includes periodic and independent tasks with deadlines equal to periods. Since the multiprocessor utilization bounds depend on the allocation algorithm, different allocation algorithms have been considered, ranging from simple heuristics to optimal allocation algorithms. As multiprocessor utilization bounds for EDF scheduling depend strongly on task sizes, all these bounds have been obtained as a function of a parameter which takes task sizes into account. Theoretically, the utilization bounds for multiprocessor EDF scheduling can be considered a partial solution to the bin--packing problem, which is known to be NP-complete. The basic task model is extended to include resource sharing, release jitter, deadlines less than periods, aperiodic tasks, non-preemptive sections, context switches, and mode changes.
BibTeX:
@article{Lopez2004a,
  author = {López, José M. and Díaz, José L. and García, Daniel F.},
  title = {Utilization Bounds for EDF Scheduling on Real--Time Multiprocessor Systems},
  journal = {Real--Time Systems},
  year = {2004},
  volume = {28},
  number = {1},
  pages = {39--68},
  url = {papers/Lopez2004a.pdf},
  doi = {http://doi.org/10.1023/B:TIME.0000033378.56741.14}
}
López, J.M., García, M., Díaz, J.L. and García, D.F. Worst--Case Utilization Bound for EDF Scheduling on Real-Time Multiprocessor Systems 2000 Proceedings of the 12th Euromicro Conference on Real--time Systems (ECRTS), pp. 25-33  inproceedings DOI URL 
Abstract: Presents the utilization bound for earliest deadline first (EDF) scheduling on homogeneous multiprocessor systems with partitioning strategies. Assuming that tasks are pre--emptively scheduled on each processor according to the EDF algorithm, and allocated according to the first-fit (FF) heuristic, we prove that the worst-case achievable utilization is 0.5(n+1), where n is the number of processors. This bound is valid for arbitrary utilization factors. Moreover, if all the tasks have utilization factors under a value α, the previous bound is raised, and the new utilization bound considering α is calculated. In addition, we prove that no uniprocessor scheduling algorithm/allocation algorithm pair can provide a higher worst-case achievable utilization than that of EDF-FF. Finally, simulation provides the average-case achievable utilization for EDF-FF.
BibTeX:
@inproceedings{Lopez2000,
  author = {López, José M. and García, M. and Díaz, José L. and García, Daniel F.},
  title = {Worst--Case Utilization Bound for EDF Scheduling on Real-Time Multiprocessor Systems},
  booktitle = {Proceedings of the 12th Euromicro Conference on Real--time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2000},
  pages = {25--33},
  url = {papers/Lopez2000.pdf},
  doi = {http://doi.org/10.1109/EMRTS.2000.853989}
}
Louise, S. Calcul de Majorants Sûrs de Temps d'Exécution au Pire pour des Tâches d'Applications Temps--réel Critiques pour des Systèmes Disposant de Caches Mémoire 2002 School: Université Paris XI  phdthesis URL 
Abstract: Ce mémoire présente une nouvelle approche pour le calcul de temps d'exécution au pire (WCET) de tâche temps--réel critique, en particulier en ce qui concerne les aléas dus aux caches mémoire. Le point général est fait sur la problématique et l'état de l'art en la matière, mais l'accent est mis sur la théorie elle-même et son formalisme, d'abord dans le cadre monotâche puis dans le cadre multitâche. La méthode utilisée repose sur une technique d'interprétation abstraite, comme la plupart des autres méthodes de calcul de WCET, mais le formalisme est dans une approche probabiliste (bien que déterministe dans le cadre monotâche) de par l'utilisation de chapines de Markov. La généralisation au cadre multitâche utilise les propriétés probabilistes pour faire une évaluation pessimiste d'un WCET et d'un écart type au pire, grâce à une modification astucieuse du propagateur dans ce cadre. Des premières évaluations du modèle, codées à la main à partir des résultats de compilation d'applications assez simples montrent des résultats prometteurs quant à l'application du modèle sur des programmes réels en vraie grandeur.
BibTeX:
@phdthesis{Louise2002a,
  author = {Louise, Stéphane},
  title = {Calcul de Majorants Sûrs de Temps d'Exécution au Pire pour des Tâches d'Applications Temps--réel Critiques pour des Systèmes Disposant de Caches Mémoire},
  school = {Université Paris XI},
  year = {2002},
  url = {papers/Louise2002a.pdf}
}
Louise, S., David, V., Delcoigne, J. and Aussaguès, C. OASIS project: deterministic real--time for safety critical embedded systems 2002 Proceedings of the 10th ACM SIGOPS European Workshop, pp. 4  inproceedings DOI URL 
Abstract: Safety critical systems is a growing industrial concern. It is a particular and long time interest for embedded or I&C systems, in nuclear power plant or aircraft applications. Since automotive industry is to use more and more microcontrollers or microprocessors with software in the near future[Bre01], concerns about safety of these systems is becoming mainstream. At the system level, because of intrinsic complexity, it is difficult to guarantee a high dependability. Typical applications should be able to manage numerous control tasks with several different time scales. They does not only demand correctness of algorithms, but also a correct management of tight time constraints, usually dictated by the environment. For system and application design, there is a conflicting interest between algorithm design and time scheduling design. Algorithm design favors a task per targeted control and so a multitasking approach. Time scheduling, on the other hand, has to take care of both strict and precise local chain of events, that needs a careful design in a multitasking environment, and mostly independent events at the system scale, more multitasking prone. One of the highest difficulties arises from the possible existence of very different time scales.
BibTeX:
@inproceedings{Louise2002,
  author = {Louise, Stéphane and David, Vincent and Delcoigne, Jean and Aussaguès, Christophe},
  title = {OASIS project: deterministic real--time for safety critical embedded systems},
  booktitle = {Proceedings of the 10th ACM SIGOPS European Workshop},
  publisher = {ACM},
  year = {2002},
  pages = {4},
  url = {papers/Louise2002.pdf},
  doi = {http://doi.org/10.1145/1133373.1133419}
}
Louise, S., Lemerre, M., Aussaguès, C. and David, V. The OASIS Kernel: A Framework for High Dependability Real--Time Systems 2011 Proceedings of the 13th IEEE International Symposium on High--Assurance Systems Engineering (HASE), pp. 95-103  inproceedings DOI URL 
Abstract: This paper presents the design and some aspects of implementation of a highly dependable, safety--oriented kernel for real-time applications. It is specifically designed as an execution facility for a deterministic semi-formal model -- the OASIS model -- which allows to express and verify temporal behaviors and communications of a safety critical real-time application. This paper shows specifically how, from a formalism, and a Domain Specific Language, we achieved to build a generic execution layer that conforms to the highest levels of safety, how the safety is implemented thank to the interaction between the kernel and the compilation tools, and how performance was optimized within these constraints.
BibTeX:
@inproceedings{Louise2011,
  author = {Louise, Stéphane and Lemerre, Matthieu and Aussaguès, Christophe and David, Vincent},
  title = {The OASIS Kernel: A Framework for High Dependability Real--Time Systems},
  booktitle = {Proceedings of the 13th IEEE International Symposium on High--Assurance Systems Engineering (HASE)},
  publisher = {IEEE Computer Society},
  year = {2011},
  pages = {95--103},
  url = {papers/Louise2011.pdf},
  doi = {http://doi.org/10.1109/HASE.2011.38}
}
Lozoya, C., Velasco, M. and Martí, P. The One--Shot Task Model for Robust Real-Time Embedded Control Systems 2008 IEEE Transactions on Industrial Informatics
Vol. 4(3), pp. 164-174 
article DOI URL 
Abstract: Embedded control systems are often implemented in small microprocessors enabled with real--time technology. In this context, control laws are often designed according to discrete-time control systems theory and implemented as hard real-time periodic tasks. Standard discrete-time control theory mandates to periodically sample (input) and actuate (output). Depending on how input/output (I/O) operations are performed within the hard real-time periodic task, different control task models can be distinguished. However, existing task models present important drawbacks. They generate task executions prone to violate the periodic control demands, a problem known as sampling and latency jitter, or they impose synchronized I/O operations at each task job execution that produce a constant but artificially long I/O latency. In this paper, the one-shot task model for implementing control systems in embedded multitasking hard real-time platforms is presented. The novel control task model is built upon control theoretical results that indicate that standard control laws can be implemented considering only periodic actuation. Taking advantage of this property, the one-shot task model is shown to remove endemic problems for real-time control systems such as sampling and latency jitters. In addition, it can minimize the harmful effects that long I/O latencies have on control performance. Extensive simulations and real experiments show the feasibility and effectiveness of the novel task model, compared to previous real-time and/or control-based solutions.
BibTeX:
@article{Lozoya2008,
  author = {Lozoya, Camilo and Velasco, Manel and Martí, Pau},
  title = {The One--Shot Task Model for Robust Real-Time Embedded Control Systems},
  journal = {IEEE Transactions on Industrial Informatics},
  year = {2008},
  volume = {4},
  number = {3},
  pages = {164--174},
  url = {papers/Lozoya2008.pdf},
  doi = {http://doi.org/10.1109/TII.2008.2002702}
}
Lunniss, W., Altmeyer, S., Lipari, G. and Davis, R.I. Accounting for Cache Related Pre--emption Delays in Hierarchical Scheduling 2014 Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS), pp. 183-192  inproceedings DOI URL 
Abstract: Hierarchical scheduling provides a means of composing multiple real--time applications onto a single processor such that the temporal requirements of each application are met. This has become a popular technique in industry as it allows applications from multiple vendors as well as legacy applications to co-exist in isolation on the same platform. However, performance enhancing features such as caches mean that one application can interfere with another by evicting blocks from cache that were in use by another application, violating the requirement of temporal isolation. While one solution is to flush the cache after every application context switch, this can potentially lead to a degradation in performance. In this paper, we present analysis that bounds the additional delay due to blocks being evicted from cache by other applications in a system using hierarchical scheduling.
BibTeX:
@inproceedings{Lunniss2014,
  author = {Lunniss, Will and Altmeyer, Sebastian and Lipari, Giuseppe and Davis, Robert Ian},
  title = {Accounting for Cache Related Pre--emption Delays in Hierarchical Scheduling},
  booktitle = {Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS)},
  publisher = {ACM Press},
  year = {2014},
  pages = {183--192},
  url = {papers/Lunniss2014.pdf},
  doi = {http://doi.org/10.1145/2659787.2659797}
}
Lupu, I., Courbin, P., George, L. and Goossens, J. Multi--Criteria Evaluation of Partitioning Schemes for Real-Time Systems 2010 Proceedings of the 15th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA), pp. 1-8  inproceedings DOI URL 
Abstract: In this paper we study the partitioning approach for multiprocessor real--time scheduling. This approach seems to be the easiest since, once the partitioning of the task set has been done, the problem reduces to well understood uniprocessor issues. Meanwhile, there is no optimal and polynomial solution to partition tasks on processors. In this paper we analyze partitioning algorithms from several points of view such that for a given task set and specific constraints (processor number, task set type, etc.) we should be able to identify the best heuristic and the best schedulability test. We also analyze the influence of the heuristics on the performance of the uniprocessor tests and the impact of a specific task order on the schedulability. A study on performance difference between Fixed Priority schedulers and EDF in the case of partitioned scheduling is also considered.
BibTeX:
@inproceedings{Lupu2010,
  author = {Lupu, Irina and Courbin, Pierre and George, Laurent and Goossens, Joël},
  title = {Multi--Criteria Evaluation of Partitioning Schemes for Real-Time Systems},
  booktitle = {Proceedings of the 15th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {1--8},
  url = {papers/Lupu2010.pdf},
  doi = {http://doi.org/10.1109/ETFA.2010.5641218}
}
Manabe, Y. and Aoyagi, S. A Feasibility Decision Algorithm for Rate Monotonic and Deadline Monotonic Scheduling 1998 Real--Time Systems
Vol. 2(14), pp. 171-181 
article DOI URL 
Abstract: Rate monotonic and deadline monotonic scheduling are commonly used for periodic real--time task systems. This paper discusses a feasibility decision for a given real-time task system when the system is scheduled by rate monotonic and deadline monotonic scheduling. The time complexity of existing feasibility decision algorithms depends on both the number of tasks and maximum periods or deadlines when the periods and deadlines are integers. This paper presents a new necessary and sufficient condition for a given task system to be feasible and proposes a new feasibility decision algorithm based on that condition. The time complexity of this algorithm depends solely on the number of tasks. This condition can also be applied as a sufficient condition for a task system using priority inheritance protocols to be feasible with rate monotonic and deadline monotonic scheduling.
BibTeX:
@article{Manabe1998,
  author = {Manabe, Yoshifumi and Aoyagi, Shigemi},
  title = {A Feasibility Decision Algorithm for Rate Monotonic and Deadline Monotonic Scheduling},
  journal = {Real--Time Systems},
  year = {1998},
  volume = {2},
  number = {14},
  pages = {171--181},
  url = {papers/Manabe1998.pdf},
  doi = {http://doi.org/10.1023/A:1007964900035}
}
Manimaran, G. and Murthy, C. A fault--tolerant dynamic scheduling algorithm for multiprocessor real-time systems and its analysis 1998 IEEE Transactions on Parallel and Distributed Systems
Vol. 9(11), pp. 1137 - 1152 
article DOI URL 
Abstract: Many time--critical applications require dynamic scheduling with predictable performance. Tasks corresponding to these applications have deadlines to be met despite the presence of faults. In this paper, we propose an algorithm to dynamically schedule arriving real-time tasks with resource and fault-tolerant requirements on to multiprocessor systems. The tasks are assumed to be nonpreemptable and each task has two copies (versions) which are mutually excluded in space, as well as in time in the schedule, to handle permanent processor failures and to obtain better performance, respectively. Our algorithm can tolerate more than one fault at a time, and employs performance improving techniques such as 1) distance concept which decides the relative position of the two copies of a task in the task queue, 2) flexible backup overloading, which introduces a trade-off between degree of fault tolerance and performance, and 3) resource reclaiming, which reclaims resources both from deallocated backups and early completing tasks. We quantify, through simulation studies, the effectiveness of each of these techniques in improving the guarantee ratio, which is defined as the percentage of total tasks, arrived in the system, whose deadlines are met. Also, we compare through simulation studies the performance our algorithm with a best known algorithm for the problem, and show analytically the importance of distance parameter in fault-tolerant dynamic scheduling in multiprocessor real-time systems.
BibTeX:
@article{Manimaran1998,
  author = {Manimaran, G. and Murthy, C.S.R.},
  title = {A fault--tolerant dynamic scheduling algorithm for multiprocessor real-time systems and its analysis},
  journal = {IEEE Transactions on Parallel and Distributed Systems},
  year = {1998},
  volume = {9},
  number = {11},
  pages = {1137 -- 1152},
  url = {papers/Manimaran1998.pdf},
  doi = {http://doi.org/10.1109/71.735960}
}
Marescaux, T., Bartic, A., Verkest, D., Vernalde, S. and Lauwereins, R. Interconnection Networks Enable Fine--Grain Dynamic Multi-tasking on FPGAs 2002
Vol. 2438Proceedings of the 12th International Conference on Field--Programmable Logic and Applications (FPL), pp. 741-763 
inproceedings DOI URL 
BibTeX:
@inproceedings{Marescaux2002,
  author = {Marescaux, Théodore and Bartic, Andrei and Verkest, Dideriek and Vernalde, Serge and Lauwereins, Rudy},
  title = {Interconnection Networks Enable Fine--Grain Dynamic Multi-tasking on FPGAs},
  booktitle = {Proceedings of the 12th International Conference on Field--Programmable Logic and Applications (FPL)},
  publisher = {Springer Berlin / Heidelberg},
  year = {2002},
  volume = {2438},
  pages = {741--763},
  url = {papers/Marescaux2002.pdf},
  doi = {http://doi.org/10.1007/3--540-46117-5_82}
}
Marinho, J., Raravi, G., Nélis, V. and Petters, S.M. Partitioned Scheduling of Multimode Systems on Multiprocessor Platforms: when to do the Mode Transition? 2011 Proceedings of the 2nd International Real--Time Scheduling Open Problems Seminar (RTSOPS)  inproceedings URL 
BibTeX:
@inproceedings{Marinho2011,
  author = {Marinho, José and Raravi, Gurulingesh and Nélis, Vincent and Petters, Stefan M.},
  title = {Partitioned Scheduling of Multimode Systems on Multiprocessor Platforms: when to do the Mode Transition?},
  booktitle = {Proceedings of the 2nd International Real--Time Scheduling Open Problems Seminar (RTSOPS)},
  year = {2011},
  url = {papers/Marinho2011.pdf}
}
Martin, S. Maîtrise de la dimension temporelle de la qualité de service dans les réseaux 2004 School: Université Paris XII Val de Marne  phdthesis URL 
BibTeX:
@phdthesis{Martin2004,
  author = {Martin, Steven},
  title = {Maîtrise de la dimension temporelle de la qualité de service dans les réseaux},
  school = {Université Paris XII Val de Marne},
  year = {2004},
  url = {papers/Martin2004.pdf}
}
Martin, S. and Minet, P. Schedulability analysis of flows scheduled with FIFO: application to the expedited forwarding class 2006 Proceedings of the 20th IEEE International Parallel and Distributed Processing Symposium (IPDPS), pp. 8  inproceedings DOI URL 
Abstract: In this paper, we are interested in real--time flows requiring quantitative and deterministic QoS (quality of service) guarantees. We focus more particularly on two QoS parameters: the worst case end-to-end response time and jitter. We consider a FIFO (first in first out) scheduling of flows. The FIFO scheduling is the simplest one to implement and very used. We first establish a bound on the worst case end-to-end response time of any flow in the network, using the trajectory approach. We present an example illustrating our results. Finally, we show how to apply these results to the EF (expedited forwarding) class in a DiffServ (differentiated services) architecture.
BibTeX:
@inproceedings{Martin2006,
  author = {Martin, Steven and Minet, Pascale},
  title = {Schedulability analysis of flows scheduled with FIFO: application to the expedited forwarding class},
  booktitle = {Proceedings of the 20th IEEE International Parallel and Distributed Processing Symposium (IPDPS)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {8},
  url = {papers/Martin2006.pdf},
  doi = {http://doi.org/10.1109/IPDPS.2006.1639424}
}
Martin, S. and Minet, P. Worst case end--to-end response times of flows scheduled with FP/FIFO 2006 Proceeding of International Conference on Networking (ICN), pp. 54-60  inproceedings  
BibTeX:
@inproceedings{Martin2006a,
  author = {Martin, Steven and Minet, Pascale},
  title = {Worst case end--to-end response times of flows scheduled with FP/FIFO},
  booktitle = {Proceeding of International Conference on Networking (ICN)},
  year = {2006},
  pages = {54--60}
}
Masmano, M., Ripoll, I. and Crespo, A. An overview of the XtratuM nanokernel 2005 In Proceedings of the 1st Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT)  inproceedings  
Abstract: This paper presents a new nanokernel (XtratuM) which is aimed for executing several operating systems (where, at least, one of them is a real-time operating system) in the same hardware with temporal and spatial isolation. Simplicity is the main idea behind of its design, therefore XtratuM can be defined as a thin layer of software which abstract the essential devices to run a kernel: the memory, the timers and the interrupts. Besides, this paper presents the ARINC specification 653-1, an interface specification which allows to build high-reliability applications, being this interface a solid candidate to be the future XtratuM interface.
BibTeX:
@inproceedings{Masmano2005,
  author = {Masmano, Miguel and Ripoll, Ismael and Crespo, Alfons},
  title = {An overview of the XtratuM nanokernel},
  booktitle = {In Proceedings of the 1st Workshop on Operating Systems Platforms for Embedded Real-Time Applications (OSPERT)},
  year = {2005}
}
Masmano, M., Ripoll, I. and Crespo Alfons, M.J.-J. XtratuM: a hypervisor for safety critical embedded systems 2009 Proceedings of the 11th Real-Time Linux Workshop, pp. 263-272  inproceedings URL 
Abstract: XtratuM is an hypervisor designed to meet safety critical requirements. Initially designed for x86 architectures (version 2.0), it has been strongly redesigned for SPARC v8 arquitecture and specially for the to the LEON2 processor. Current version 2.2, includes all the functionalities required to build safety critical systems based on ARINC 653, AUTOSTAR and other standards. Although XtratuMdoes not provides a compliant API with these standards, partitions can offer easily the appropriated API to the applications. XtratuM is being used by the aerospace sector to build software building blocks of future generic on board software dedicated to payloads management units in aerospace.
XtratuM provides ARINC 653 scheduling policy, partition management, inter-partition communications, health monitoring, logbooks, traces, and other services to easily been adapted to the ARINC standard. The configuration of the system is specified in a configuration file (XML format) and it is compiled to achieve a static configuration of the final container (XtratuM and the partition’s code) to be deployed to the hardware board. As far as we know, XtratuM is the first hypervisor for the SPARC v8 arquitecture.
In this paper, the main design aspects are discussed and the internal architecture described. An evaluation of the most significant metrics is also provided. This evaluation permits to affirm that the overhead of a hypervisor is lower than 3% if the slot duration is higher than 1 millisecond.
BibTeX:
@inproceedings{Masmano2009,
  author = {Masmano, Miguel and Ripoll, Ismael and Crespo, Alfons, Metge, Jean-Jacques},
  title = {XtratuM: a hypervisor for safety critical embedded systems},
  booktitle = {Proceedings of the 11th Real-Time Linux Workshop},
  year = {2009},
  pages = {263--272},
  url = {/papers/Masmano2009.pdf}
}
Masrur, A., Kindt, P., Becker, M., Chakraborty, S., Kleeberger, V., Barke, M. and Schlichtmann, U. Schedulability Analysis for Processors with Aging--Aware Autonomic Frequency Scaling 2012 Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 11-20  inproceedings DOI URL 
Abstract: With the rapid progress in semiconductor technology and the shrinking of device geometries, the resulting processors are increasingly becoming prone to effects like aging and soft errors. As a processor ages, its electrical characteristics degrade, i.e., the switching times of its transistors increase. Hence, the processor cannot continue error--free operation at the same clock frequency and/or voltage for which it was originally designed. In order to mitigate such effects, recent research proposes to equip processors with special circuitry that automatically adapts its clock frequency in response to changes in its circuit-level timing properties (arising from changes in its electrical characteristics). From the point of view of tasks running on these processors, such autonomic frequency scaling(AFS) processors become slower as they gradually age. This leads to additional execution delay for tasks, which needs to be analyzed carefully, particularly in the context of hard real time or safety-critical systems. Hence, for real-time systems based on AFS processors, the associated schedulability analysis should be aging-aware which is a relatively unexplored topic so far. In this paper we propose a schedulability analysis framework that accounts such aging-induced degradation and changes in timing properties of the processor, when designing hard real-time systems. In particular, we address the schedulability and task mapping problem by taking a lifetime constraint of the system into account. In other words, the system should be designed to be fully operational (i.e., meet all deadlines) till a given minimum period of time (i.e., its lifetime). The proposed framework is based on an aging model of the processor which we discuss in detail. In addition to studying the effects of aging on the schedulability of real-time tasks, we also discuss its impact on task mapping and resource dimensioning.
BibTeX:
@inproceedings{Masrur2012,
  author = {Masrur, Alejandro and Kindt, Philipp and Becker, Martin and Chakraborty, Samarjit and Kleeberger, Veit and Barke, Martin and Schlichtmann, Ulf},
  title = {Schedulability Analysis for Processors with Aging--Aware Autonomic Frequency Scaling},
  booktitle = {Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {11--20},
  url = {papers/Masrur2012.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2012.57}
}
Masson, D. Intégration des événements non périodiques dans les systèmes temps réel – Application à la gestion des événements dans la spécification temps réel pour Java 2008 School: Université Paris--Est  phdthesis URL 
Abstract: Les systèmes temps réel sont des systèmes informatiques composés de tâches auxquelles sont associées des contraintes temporelles, appelées échéances. Dans notre étude, nous distinguons deux familles de tâches : les tâches temps réel dur et les tâches temps réel souple. Les premières possèdent une échéance dure, ce qui signifie qu'elles doivent impérativement la respecter. Elles sont par nature périodiques, ou sporadiques, et l'étude analytique de leur comportement fait l'objet d'un état de l'art conséquent. Les secondes sont de nature apériodique. Aucune hypothèse sur leur modèle d'arrivée ni sur leur nombre n'est possible. Aucune garantie ne saurait être donnée sur leur comportement dès lors que l'on ne peut écarter les situations de surcharge, où la demande de calcul peut dépasser les capacités du système. La problématique devient alors l'étude des solutions d'ordonnancement mixte qui minimisent les temps de réponse des tâches apériodiques tout en garantissant les échéances des tâches périodiques. De nombreuses solutions ont été proposées ces vingt dernières années. On distingue les solutions basées sur la réservation de ressources, les serveurs de tâches, des solutions exploitant les instants d'inactivité du système, comme les algorithmes de vol de temps creux. La spécification Java pour le temps réel (RTSJ) voit le jour dans les années 2000. Si cette norme répond à de nombreux problèmes liés à la mémoire ou à l'ordonnancement des tâches périodiques, le problème de l'ordonnancement mixte de tâches périodiques et apériodiques n'est pas abordé. Nous proposons dans cette thèse d'apporter les modifications nécessaires aux algorithmes principaux d'ordonnancement mixtes, le Polling Server (PS), le Deferrable Server (DS) et le Dynamic Approximate Slack Stealer (DASS) en vue de leur implantation avec RTSJ. Ces algorithmes ne peuvent en effet être implantés directement tels qu'ils sont décrits, car ils sont trop liés à l'ordonnanceur du système. Nous proposons des extensions aux APIs RTSJ existantes pour faciliter l'implantation de ces mécanismes modifiés, et nous fournissons les interfaces utiles a l'ajout d'autres solutions algorithmiques. Nous proposons également des modifications sur les APIs existantes de RTSJ afin de répondre aux problèmes d'intégration et d'implantation d'algorithmes d'analyse de faisabilité. Nous proposons enfin un algorithme d'estimation des temps creux, le Minimal Approximate Slack Stealer (MASS), dont l'implantation au niveau utilisateur, permet son intégration dans RTSJ.
BibTeX:
@phdthesis{Masson2008a,
  author = {Masson, Damien},
  title = {Intégration des événements non périodiques dans les systèmes temps réel – Application à la gestion des événements dans la spécification temps réel pour Java},
  school = {Université Paris--Est},
  year = {2008},
  url = {papers/Masson2008a.pdf}
}
Masson, D. and Midonnet, S. Userland Approximate Slack Stealer with Low Time Complexity 2008 Proceedings of the 16th Real--Time and Network Systems (RTNS), pp. 29-38  inproceedings URL 
Abstract: The aim of our work is to provide a mechanism to deal with soft real--time aperiodic traffic on top of a fixed priority scheduler, without any kind of modification on it. We want to reduce as most as possible the time and implementation complexities of this mechanism. Moreover, the overhead of the framework has to be completely integrated in the feasibility analysis process. We propose a naive but low cost slack time estimation algorithm and discuss the issue of its utilization at the user level. We validate our work by extensive simulations and illustrate its utility by an implementation on top of the Real-Time Specification for Java (RTSJ).
BibTeX:
@inproceedings{Masson2008,
  author = {Masson, Damien and Midonnet, Serge},
  title = {Userland Approximate Slack Stealer with Low Time Complexity},
  booktitle = {Proceedings of the 16th Real--Time and Network Systems (RTNS)},
  year = {2008},
  pages = {29--38},
  url = {papers/Masson2008.pdf}
}
Maxim, C., Gogonel, A., Asavoae, I., Asavoae, M., Cucu-Grosjean, L. and Talaboulma, W. Reproducibility and representativity - mandatory properties for the compositionality of measurement-based WCET estimation approaches 2016 Proceedings of the 9th International Workshop on Compositional Theory and Technology for Real-Time Embedded System (CRTS), pp. 17-24  inproceedings URL 
Abstract: The increased number of systems consisting of multiple interacting components imposes the evolution of timing analyses towards methods able to estimate the timing behavior of an entire system by aggregating timings bounds of its components. In this paper we propose the first discussion on the properties required by measurement-based timing analyses to ensure such compositionality. We identify the properties of reproducibility and representativity as necessary conditions to ensure the convergence of any measurement protocol allowing a compositional measurement-based timing analysis.
BibTeX:
@inproceedings{Maxim2016,
  author = {Maxim, Cristian and Gogonel, Adriana and Asavoae, Irina and Asavoae, Mihail and Cucu-Grosjean, Liliana and Talaboulma, Walid},
  title = {Reproducibility and representativity - mandatory properties for the compositionality of measurement-based WCET estimation approaches},
  booktitle = {Proceedings of the 9th International Workshop on Compositional Theory and Technology for Real-Time Embedded System (CRTS)},
  year = {2016},
  pages = {17--24},
  url = {/papers/Maxim2016.pdf}
}
Maxim, D. Probabilistic analysis of real-time systems 2013 School: Université de Lorraine  phdthesis URL 
Abstract: Critical real--time embedded systems integrate complex architectures that evolve constantly in order to provide new functionality required by the end users of the systems (automotive, avionics, railway, etc). These new architectures have a direct impact on the variability of the timing behavior of the real-time system. This variability leads to important over-provisioning if the design of the system is based only on worst case reasoning. Probabilistic approaches propose solutions are based on the probability of occurrence of the worst case values in order to avoid over provisioning while satisfying real-time constraints. The main objectives of this work are new analysis techniques for probabilistic real-time systems and ways of decreasing the complexity of these analyses, as well as to propose optimal xed priority scheduling algorithms for systems that have variability at the level of execution times. The results that we provide in this work have been proved applicable to hard real-time systems, which are the main focus of our work. Our proposed analysis for systems with multiple probabilistic parameters has been shown to greatly decrease the pessimism introduced by other types of analyses. This type of analysis combined with the proper optimal scheduling algorithms for probabilistic real-time system help the system designers to better appreciate the feasibility of a system, especially of those that are deemed unfeasible by deterministic analyses/scheduling algorithms.
BibTeX:
@phdthesis{Maxim2013,
  author = {Maxim, Dorin},
  title = {Probabilistic analysis of real-time systems},
  school = {Université de Lorraine},
  year = {2013},
  url = {papers/Maxim2013.pdf}
}
Medlej, S., Martin, S. and Cottin, J.-M. Identifying Source of Pessimism in the Trajectory Approach with FIFO Scheduling 2012 Proceedings of Embedded Real--Time Software and Systems (ERTS²)  inproceedings URL 
Abstract: witched Ethernet has been used in critical industrial networks such as in avionic and nuclear sectors. For qualification purposes, before deploying the network, we are interested in computing deterministic upper bounds on the end--to-end response time of flows existing in the network. This paper focuses on one of the approaches that can be used to determine an upper bound on the end-to-end response time of a flow. It is called the Trajectory Approach. We describe briefly the concept on which this approach is based. Moreover, we identify the source of pessimism introduced by this approach in the case of FIFO scheduling. Finally, we show on a small network configuration how the sources of pessimism may affect the tightness of the upper bound of the end-to-end response time computed using the Trajectory Approach.
BibTeX:
@inproceedings{Medlej2012,
  author = {Medlej, Sara and Martin, Steven and Cottin, Jean--Marie},
  title = {Identifying Source of Pessimism in the Trajectory Approach with FIFO Scheduling},
  booktitle = {Proceedings of Embedded Real--Time Software and Systems (ERTS²)},
  year = {2012},
  url = {papers/Medlej2012.pdf}
}
Mégel, T. Placement, ordonnancement et mécanismes de migration de tâches temps--réel pour des architectures distribuées multicœurs 2012 School: Université de Toulouse  phdthesis URL 
Abstract: Les systèmes temps--réel embarqués critiques intègrent un nombre croissant de fonctionnalités comme le montrent les domaines de l’automobile ou de l’aéronautique. Ces systèmes doivent offrir un niveau maximal de sûreté de fonctionnement en disposant des mécanismes pour traiter les défaillances éventuelles et doivent être également performants, avec le respect de contraintes temps-réel strictes. Ces systèmes sont en outre contraints par leur nature embarquée : les ressources sont limitées, tels que par exemple leur espace mémoire et leur capacité de calcul. Dans cette thèse, nous traitons deux problématiques principales de ce type de systèmes. La première porte sur la manière d’apporter une meilleure tolérance aux fautes dans les systèmes temps-réel distribués subissant des défaillances matérielles multiples et permanentes. Ces systèmes sont souvent conçus avec une allocation statique des tâches. Une approche plus flexible effectuant des reconfigurations est utile si elle permet d’optimiser l’allocation à chaque défaillance rencontrée, pour les ressources restantes. Nous proposons une telle approche hors-ligne assurant un dimensionnement adapté pour prendre en compte les ressources nécessaires à l’exécution de ces actions. Ces reconfigurations peuvent demander une réallocation des tâches ou répliques si l’espace mémoire local est limité. Dans un contexte temps-réel strict, nous définissons notamment des mécanismes et des techniques de migration garantissant l’ordonnançabilité globale du système. La deuxième problématique se focalise sur l’optimisation de l’exécution des tâches au niveau local dans un contexte multicœurs préemptif. Nous proposons une méthode d’ordonnancement optimal disposant d’une meilleure extensibilité que les approches existantes en minimisant les surcoûts : le nombre de changements de contexte (préemptions et migrations locales) et la complexité de l’ordonnanceur.
BibTeX:
@phdthesis{Megel2012,
  author = {Mégel, Thomas},
  title = {Placement, ordonnancement et mécanismes de migration de tâches temps--réel pour des architectures distribuées multicœurs},
  school = {Université de Toulouse},
  year = {2012},
  url = {papers/Megel2012.pdf}
}
Mégel, T., Sirdey, R. and David, V. Minimizing Task Preemptions and Migrations in Multiprocessor Optimal Real--Time Schedules 2010 Proceedings of the 31st IEEE Real--Time Systems Symposium (RTSS), pp. 37-46  inproceedings DOI URL 
Abstract: We present a new approach to decrease task preemptions and migrations in optimal global real--time schedules on symmetric multiprocessors. Contrary to classical approaches, our method proceeds in two steps, one off-line to place jobs on intervals and one on-line to schedule them dynamically inside each interval. We propose a new linear programming formulation and a local scheduler which exhibits low complexity and produces few task preemptions and migrations. We compare our approach with other optimal scheduling algorithms, using the implicit-deadline periodic task model. Simulation results illustrate the competitiveness of our approach with respect to task preemptions and migrations.
BibTeX:
@inproceedings{Megel2010,
  author = {Mégel, Thomas and Sirdey, Renaud and David, Vincent},
  title = {Minimizing Task Preemptions and Migrations in Multiprocessor Optimal Real--Time Schedules},
  booktitle = {Proceedings of the 31st IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {37--46},
  url = {papers/Megel2010.pdf},
  doi = {http://doi.org/10.1109/RTSS.2010.22}
}
Mekki-Mokhtar, A., Blanquart, J.-p., Guiochet, J., Powell, D. and Roy, M. Safety Trigger Conditions for Critical Autonomous Systems 2012 Proceedings of the 18th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC), pp. 61-69  inproceedings DOI URL 
Abstract: A systematic process for eliciting safety trigger conditions is presented. Starting from a risk analysis of the monitored system, critical transitions to catastrophic system states are identified and handled in order to specify safety margins on them. The conditions for existence of such safety margins are given and an alternative solution is proposed if no safety margin can be defined. The proposed process is illustrated on a robotic rollator.
BibTeX:
@inproceedings{Mekki--Mokhtar2012,
  author = {Mekki--Mokhtar, Amina and Blanquart, Jean-paul and Guiochet, Jérémie and Powell, David and Roy, Matthieu},
  title = {Safety Trigger Conditions for Critical Autonomous Systems},
  booktitle = {Proceedings of the 18th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {61--69},
  url = {papers/Mekki--Mokhtar2012.pdf},
  doi = {http://doi.org/10.1109/PRDC.2012.22}
}
Merino, P., Jacome, M. and López, J.C. A methodology for task based partitioning and scheduling of dynamically reconfigurable systems 1998 In Proceedings of IEEE Symposium on FPGAs for Custom Computing Machines (FCCM), pp. 324-325  inproceedings DOI URL 
Abstract: Taking maximum advantage of dynamic reconfiguration in the implementation of digital systems poses a number of challenging research problems. Specifically, techniques are needed to partition the system behavioral description into segments of computation (or “scheduling units”), and to define a reconfiguration schedule with respect to those units, so as to maximize the performance of the dynamically reconfigurable system, subject to the area constraints of the FPGA. We propose a methodology to: (1) perform a coarse--grained partitioning of the system behavioral description into a set of tasks, (2) determine which sub-set of tasks is to remain resident in the FPGA, and which sub-set is to be non resident, (3) generate a reconfiguration schedule for the non-resident tasks by specifying when such tasks should be loaded on to and erased from the FPGA.
BibTeX:
@inproceedings{Merino1998,
  author = {Merino, Pedro and Jacome, Margarida and López, Juan Carlos},
  title = {A methodology for task based partitioning and scheduling of dynamically reconfigurable systems},
  booktitle = {In Proceedings of IEEE Symposium on FPGAs for Custom Computing Machines (FCCM)},
  publisher = {IEEE Computer Society},
  year = {1998},
  pages = {324--325},
  url = {papers/Merino1998.pdf},
  doi = {http://doi.org/10.1109/FPGA.1998.707937}
}
Metcalfe, R.M. and Boggs, D.R. Ethernet: distributed packet switching for local computer networks 1976 Communications of the ACM
Vol. 19(7), pp. 395-404 
article DOI URL 
Abstract: Ethernet is a branching broadcast communication system for carrying digital data packets among locally distributed computing stations. The packet transport mechanism provided by Ethernet has been used to build systems which can be viewed as either local computer networks or loosely coupled multiprocessors. An Ethernet's shared communication facility, its Ether, is a passive broadcast medium with no central control. Coordination of access to the Ether for packet broadcasts is distributed among the contending transmitting stations using controlled statistical arbitration. Switching of packets to their destinations on the Ether is distributed among the receiving stations using packet address recognition. Design principles and implementation are described based on experience with an operating Ethernet of 100 nodes along a kilometer of coaxial cable. A model for estimating performance under heavy loads and a packet protocol for error controlled communication are included for completeness.
BibTeX:
@article{Metcalfe1976,
  author = {Metcalfe, Robert M. and Boggs, David R.},
  title = {Ethernet: distributed packet switching for local computer networks},
  journal = {Communications of the ACM},
  year = {1976},
  volume = {19},
  number = {7},
  pages = {395--404},
  url = {papers/Metcalfe1976.pdf},
  doi = {http://doi.org/10.1145/360248.360253}
}
Meumeu Yomsi, P. Prise en compte du coût exact de la préemption dans l'ordonnancement temps réel monoprocesseur avec contraintes multiples 2009 School: Université Paris Sud -- Paris XI  phdthesis  
Abstract: Nous nous intéressons aux problèmes d’ordonnancement de tâches périodiques dans les systèmes temps réel critiques (durs). De tels systèmes nécessitent un respect absolu de toutes les contraintes qui les caractérisent sinon des conséquences catastrophiques peuvent survenir. Dans la littérature, il existe des algorithmes d’ordonnancement à priorités fixes permettant une analyse d’ordonnançabilité de ces systèmes. Cependant, l’approximation du coût de la préemption, qui est la partie variable du coût du système d’exploitation (OS), dans le WCET des tâches conduit à faire un compromis entre gaspillage et sûreté de l’ordonnançabilité, ce qui n’est pas satisfaisant. Quelques travaux ont été proposés pour résoudre ce problème mais les résultats conduisent à la prise en compte soit d’un nombre minimal soit d’un nombre maximal de préemptions. Par conséquent, il n’est pas possible de garantir de façon sûre l’ordonnançabilité d’un système temps réel critique. Dans cette thèse, les modèles classiques n’étant pas adaptés pour prendre en compte le coût exact de la préemption, nous introduisons un nouveau modèle pour résoudre le problème général de l’ordonnancement de systèmes temps réel durs avec des contraintes multiples telles que la précédence, la périodicité stricte, la latence et la gigue, tout en tenant compte du coût exact de la préemption pour tous les scénarii de premières activations de toutes les tâches (simultané ou non simultané). Fondé sur ce nouveau modèle, nous proposons une analyse d’ordonnançabilité qui utilise la définition d’une opération binaire d’ordonnancement ⊕ dont les opérandes sont appelés otâches. Nous montrons la correspondance entre une otâche et une tâche périodique. Nous examinons deux approches. Premièrement, nous considérons le cas où la priorité de chaque otâche est connue (Rate Monotonic, Deadline Monotonic, Audsley, etc.), conduisant ainsi à un ordre décroissant des priorités des otâches. Deuxièmement, nous considérons le cas où la priorité de chaque otâche n’est pas connue. Nous étudions de près l’impact du scénario de premières activations de toutes les otâches sur l’analyse d’ordonnançabilité. Nous prouvons d’une part que le scénario, où les premières activations de toutes les otâches sont simultanées, ne correspond pas au pire cas, et d’autre part qu’il n’existe pas un tel scénario lorsque le coût de la préemption est pris en compte. Ensuite, nous prouvons que le choix des priorités des otâches fondé sur la politique d’Audsley n’est plus applicable, ni optimal. Pour résoudre ce problème, nous proposons un algorithme optimal de choix de priorités des otâches. Ici optimal signifie que s’il existe une politique de choix des priorités qui conduit à un ordonnancement valide alors le choix des priorités proposé permettra également d’obtenir un ordonnancement valide. Nous avons développé un logiciel appelé SAS (Simulation Analysis of Scheduling)pour mettre à la disposition d’utilisateurs les résultats que nous avons obtenus. SAS est un logiciel qui effectue l’analyse d’ordonnançabilité de systèmes d’otâches périodiques dans le cas monoprocesseur. Sa principale contribution, par rapport à d’autres outils commerciaux et académiques du même type, est qu’il prend en compte le coût exact de préemption au cours de l’analyse d’ordonnançabilité avec des contraintes multiples.
BibTeX:
@phdthesis{MeumeuYomsi2009,
  author = {Meumeu Yomsi, Patrick},
  title = {Prise en compte du coût exact de la préemption dans l'ordonnancement temps réel monoprocesseur avec contraintes multiples},
  school = {Université Paris Sud -- Paris XI},
  year = {2009}
}
Meumeu Yomsi, P., Nélis, V. and Goossens, J. Scheduling Multi--Mode Real-Time Systems upon Uniform Multiprocessor Platforms 2010 Proceedings of the 15th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA), pp. 1-8  inproceedings DOI URL 
Abstract: In this paper, we address the scheduling problem of multi--mode real-time systems upon uniform multiprocessor platforms. We propose two transition protocols, specified together with their schedulability test, and provide the reader with two distinct upper bounds for the length of the transient phases during mode transitions, respectively for the cases where jobs priorities are known and unknown beforehand.
BibTeX:
@inproceedings{MeumeuYomsi2010,
  author = {Meumeu Yomsi, Patrick and Nélis, Vincent and Goossens, Joël},
  title = {Scheduling Multi--Mode Real-Time Systems upon Uniform Multiprocessor Platforms},
  booktitle = {Proceedings of the 15th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {1--8},
  url = {papers/MeumeuYomsi2010.pdf},
  doi = {http://doi.org/10.1109/ETFA.2010.5641275}
}
Meurer, R.S., Ludwich, M.K. and Fröhlich, A.A. Virtualizing Mixed-Criticality Operating Systems 2016 Proceedings of VI Brazilian Symposium on Computing Systems Engineering (SBESC)  inproceedings DOI  
Abstract: The forever growing number of embedded control units in some applications such as cars or airplanes are increasing system complexity and making harder to coordinate all this hardware. The increasing capacity of embedded hardware and the advances in virtualization technology make it possible to deal with this problem. There is a current trend to bring many of this control systems to a single platform, thus making it possible for a single hardware platform to manage a whole system with the same isolation guarantees that the use of multiple Microcontroller Units (MCUs) provides, which also implies in a reduction of cost. However, all these different applications have very different purposes and requirements, so the platform should be able to handle all of them, from human interaction to hard real-time control. In our paper, we explore Linux paravirtualization interface, paravirt_ops, to make it run on a confined Virtual Machine (VM) on top of the HyperEPOS real-time hypervisor. The virtualized Linux provides embedded systems with all the functionalities of a general purpose operating system, including human interaction and connectivity, while other VMs define a realm for the proper operation of safe-critical tasks.
BibTeX:
@inproceedings{Meurer2016,
  author = {Meurer, Rodrigo Schmitt and Ludwich, Mateus Krepsky and Fröhlich, Antônio Augusto},
  title = {Virtualizing Mixed-Criticality Operating Systems},
  booktitle = {Proceedings of VI Brazilian Symposium on Computing Systems Engineering (SBESC)},
  publisher = {IEEE},
  year = {2016},
  doi = {http://doi.org/10.1109/SBESC.2016.020}
}
Midonnet, S. and Fauberteau, F. Ordonnancement dans les systèmes temps réel 2014   inbook  
Abstract: L’objectif de ce chapitre est d’apporter au lecteur la compréhension des différentes notions liées à la synchronisation des traitements plutôt que de donner une description exhaustive des protocoles existants. Nous présenterons en détails les principaux protocoles et nous donnerons les références de ceux que le lecteur intéressé pourra consulter. Nous portons notre attention plus particulièrememnt sur les systèmes ordonnancés en priorités fixes. Et, dans le cas des architectures multiprocesseur, nous ne considérerons que le cas de l’ordonnancement par partitionnement. Ce chapitre est organisé de la manière suivante : dans la section 4.2, nous exposons la terminologie, ainsi que la notation employée. Dans la section 4.3, nous décrivons les protocoles incontournables (majeurs) aussi bien dans le cas des systèmes monoprocesseur que dans le cas des systèmes multiprocesseur. Dans la section 4.4, nous montrons les conséquences indésirables des synchronisations sur l’ordonnancement des systèmes. Nous montrons comment les éviter. Dans la section 4.5, nous nous intéressons aux conséquences des différents blocages sur l’analyse des systèmes et nous montrons comment estimer le facteur de blocage des tâches. Nous terminons ce chapitre en section 4.6 en concluant sur les différents aspects abordés.
BibTeX:
@inbook{Midonnet2014,
  author = {Midonnet, Serge and Fauberteau, Frédéric},
  title = {Ordonnancement dans les systèmes temps réel},
  publisher = {ISTE Editions},
  year = {2014}
}
Milojevic, D., Nelissen, G., Goossens, J., Berten, V. and Nélis, V. U--EDF: An Unfair But Optimal Multiprocessor Scheduling Algorithm for Sporadic Tasks 2012 Proceedings of the 24th Euromicro Conference Real--Time Systems (ECRTS), pp. 13-23  inproceedings DOI URL 
Abstract: A multiprocessor scheduling algorithm named U--EDF, was presented in [1] for the scheduling of periodic tasks with implicit deadlines. It was claimed that U-EDF is optimal for periodic tasks (i.e., it can meet all deadlines of every schedulable task set) and extensive simulations showed a drastic improvement in the number of task preemptions and migrations in comparison to state-of-the-art optimal algorithms. However, there was no proof of its optimality and U-EDF was not designed to schedule sporadic tasks. In this work, we propose a generalization of U-EDF for the scheduling of sporadic tasks with implicit deadlines, and we prove its optimality. Contrarily to all other existing optimal multiprocessor scheduling algorithms for sporadic tasks, U-EDF is not based on the fairness property. Instead, it extends the main principles of EDF so that it achieves optimality while benefiting from a substantial reduction in the number of preemptions and migrations.
BibTeX:
@inproceedings{Milojevic2012,
  author = {Milojevic, Dragomir and Nelissen, Geoffrey and Goossens, Joël and Berten, Vandy and Nélis, Vincent},
  title = {U--EDF: An Unfair But Optimal Multiprocessor Scheduling Algorithm for Sporadic Tasks},
  booktitle = {Proceedings of the 24th Euromicro Conference Real--Time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {13--23},
  url = {papers/Milojevic2012.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2012.36}
}
Mok, A.K.-L. Fundamental Design Problems of Distributed Systems for Hard--Real-Time Environments 1983 School: Massachusetts Institute of Technology  phdthesis URL 
Abstract: Software designed to function in a hard--real-time environment where strict timing constraints must be met often entails implicit assumptions about a programming language and the underlying system which supports it. Programs which are logically correct, i.e., they implement the intended algorithms, may not function correctly if their assumed timing characteristics are not met. This can occur if the programming language is not expressive enough to permit an adequate specification of the desired timing characteristics of the software or if the expressible timing characteristics cannot be verified before run time. For distributed systems in particular, the software must be tailored to a myriad of implementation parameters, e.g., communication bandwidth, thus rendering subsequent modifications hazardous. Our research investigates the basic problems in automating the design and maintenance approach to real-time software design via process-based models, we shall provide a graph-based computation model which is more suitable for expressing the computational requirements of the hard-real-time environment. This model is an extension of CONSORT (Control Structure Optimized for Real-Time), an experimental software design system which has been implemented to generates process control application programs from block diagram schemata. While our graph-based model is abstract, it can serve as a useful intermediate representation between textual requirements specifications and target application programs. Using the graph-based model, the complexity of the relevant resource allocation problems for meeting stringent timing constraints is investigated.
BibTeX:
@phdthesis{Mok1983,
  author = {Mok, Aloysius Ka--Lau},
  title = {Fundamental Design Problems of Distributed Systems for Hard--Real-Time Environments},
  school = {Massachusetts Institute of Technology},
  year = {1983},
  url = {papers/Mok1983.pdf}
}
Mollison, M.S., Erickson, J.P., Anderson, J.H., Baruah, S.K. and Scoredos, J.A. Mixed--Criticality Real-Time Scheduling for Multicore Systems 2010 Proceedings of the 10th International Conference on Computer and Information Technology (CIT), pp. 1864-1871  inproceedings DOI URL 
Abstract: Current hard real--time scheduling and analysis techniques are unable to efficiently utilize the computational bandwidth provided by multicore platforms. This is due to the large gap between worst-case execution time predictions used in schedulability analysis and actual execution times seen in practice. In this paper, we view this gap as "slack'' that can be accounted for during schedulability analysis and reclaimed for less critical work. We use this technique to develop an architecture for scheduling mixed criticality real-time workloads on multiprocessor platforms. Our architecture provides temporal isolation among tasks of different criticalities while allowing slack to be redistributed across criticality levels.
BibTeX:
@inproceedings{Mollison2010,
  author = {Mollison, Malcolm S. and Erickson, Jeremy P. and Anderson, James H. and Baruah, Sanjoy K. and Scoredos, John A.},
  title = {Mixed--Criticality Real-Time Scheduling for Multicore Systems},
  booktitle = {Proceedings of the 10th International Conference on Computer and Information Technology (CIT)},
  publisher = {IEEE Computer Society},
  year = {2010},
  pages = {1864--1871},
  url = {papers/Mollison2010.pdf},
  doi = {http://doi.org/10.1109/CIT.2010.320}
}
Moreno, G.A. and de Niz, D. An Optimal Real--Time Voltage and Frequency Scaling for Uniform Multiprocessors 2012 Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 21-30  inproceedings DOI URL 
Abstract: Power consumption is an increasing concern in real--time systems that operate on battery power or require heat dissipation to keep the system at its operating temperature. Today, most processors allow software to change their frequency and voltage of operation to reduce their power consumption. Frequency scaling in real-time systems must be done in a way that ensures that the tasks' deadlines are met. In this paper we present the Growing Minimum Frequency (GMF) algorithm for voltage and frequency scaling in uniform multiprocessors for real-time systems. This algorithm runs in polynomial time and computes the optimal voltage and frequency assignment, achieving better power efficiency than previous algorithms. We present the optimality proof and evaluate the practical improvement over previous algorithms with simulated task sets. Our evaluation shows up to to 30% power efficiency improvement over previous algorithms.
BibTeX:
@inproceedings{Moreno2012,
  author = {Moreno, Gabriel A. and de Niz, Dionisio},
  title = {An Optimal Real--Time Voltage and Frequency Scaling for Uniform Multiprocessors},
  booktitle = {Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {21--30},
  url = {papers/Moreno2012.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2012.51}
}
Nacer, A.A., Jaffres-Runser, K., Schabarg, J.-L. and Fraboul, C. Strategies for the Interconnection of CAN buses through an Ethernet switch 2013 Proceedings of the 8th International Symposium on Industrial Embedded Systems (SIES), pp. 77-80  inproceedings DOI URL 
Abstract: This paper discusses the use of an Ethernet switch to interconnect remotely located fieldbuses, e.g. CAN. Mastering delays of flows is a key issue in such architectures. The focus of this paper is to propose and analyze bridging strategies for the gateways between CAN and the Ethernet switch. Our previous studies have highlighted the benefits of an optimal design of encapsulation policies at ingress gateways to the switch. In this paper, we show that regulating CAN traffic at the egress gateways is essential as well to provide timely transport of CAN flows.
BibTeX:
@inproceedings{Nacer2013,
  author = {Nacer, Abdelaziz Ahmed and Jaffres--Runser, Katia and Schabarg, Jean-Luc and Fraboul, Christian},
  title = {Strategies for the Interconnection of CAN buses through an Ethernet switch},
  booktitle = {Proceedings of the 8th International Symposium on Industrial Embedded Systems (SIES)},
  publisher = {IEEE Computer Society},
  year = {2013},
  pages = {77--80},
  url = {papers/Nacer2013.pdf},
  doi = {http://doi.org/10.1109/SIES.2013.6601474}
}
Naderlinger, A., Pletzer, J., Pree, W. and Templ, J. Model--Driven Development of FlexRay-Based Systems with the Timing Definition Language (TDL) 2007 Proceedings of the 5th International Workshop on Software Engineering for Automotive Systems (SEAS), pp. 6  inproceedings DOI URL 
Abstract: This paper argues that a logical specification of the timing behavior, which represents the core abstraction of the Timing Definition Language (TDL), is the key to significantly reduce the development, maintenance and integration costs of FlexRay--based systems. We measured a productivity gain by a factor of 20 and more with TDL compared to state-of-the-art FlexRay development methods and tools (see Section 1). We illustrate how TDL allows the platform-independent modeling of the timing and functional behavior, and how we accomplish the automatic platform mapping. An outlook sketches future research activities.
BibTeX:
@inproceedings{Naderlinger2007,
  author = {Naderlinger, Andreas and Pletzer, Johannes and Pree, Wolfgang and Templ, Josef},
  title = {Model--Driven Development of FlexRay-Based Systems with the Timing Definition Language (TDL)},
  booktitle = {Proceedings of the 5th International Workshop on Software Engineering for Automotive Systems (SEAS)},
  year = {2007},
  pages = {6},
  url = {papers/Naderlinger2007.pdf},
  doi = {http://doi.org/10.1109/SEAS.2007.8}
}
Nasri, M. and Kargahi, M. A Method for Improving Delay--Sensitive Accuracy in Real-Time Embedded Systems 2012 Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 378-387  inproceedings DOI URL 
Abstract: Timeliness and accuracy are two major concerns in many real--time embedded systems working in dynamic environments. It has been emphasized in the literature that in various real-time applications such as control systems and Kalman filters, delay is one main source of inaccuracy in the system. In this paper, we present a solution based on scheduling algorithms for the problem of inaccuracy in such systems. To this aim, first an accuracy model is introduced for systems which their accuracy is influenced by sampling and I/O delays. Then an algorithm called adjacency trade is presented to improve system accuracy while maintaining its timeliness. This algorithm follows an iterative approach and can be applied to each priority-based scheduling algorithm with no intervention in respecting the deadlines. Finally, through various simulation experiments, the effectiveness of this algorithm is examined against some algorithms in the literature.
BibTeX:
@inproceedings{Nasri2012,
  author = {Nasri, Mitra and Kargahi, Mehdi},
  title = {A Method for Improving Delay--Sensitive Accuracy in Real-Time Embedded Systems},
  booktitle = {Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {378--387},
  url = {papers/Nasri2012.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2012.39}
}
Nélis, V. Energy--Aware Real-Time Scheduling in Embedded Multiprocessor Systems 2010 School: Université Libre de Bruxelles  phdthesis URL 
BibTeX:
@phdthesis{Nelis2010,
  author = {Nélis, Vincent},
  title = {Energy--Aware Real-Time Scheduling in Embedded Multiprocessor Systems},
  school = {Université Libre de Bruxelles},
  year = {2010},
  url = {papers/Nelis2010.pdf}
}
Nélis, V. and Goossens, J. MORA: an Energy--Aware Slack Reclamation Scheme for Scheduling Sporadic Real-Time Tasks upon Multiprocessor Platforms 2009 Proceedings of the 15th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)  inproceedings DOI URL 
Abstract: Abstract—In this paper, we address the global and preemptive energy--aware scheduling problem of sporadic constrained-deadline tasks on DVFS-identical multiprocessor platforms. We propose an online slack reclamation scheme which profits from the discrepancy between the worst- and actual-case execution time of the tasks by slowing down the speed of the processors in order to save energy. Our algorithm called MORA takes into account the application-specific consumption profile of the tasks. We demonstrate that MORA does not jeopardize the system schedulability and we show by performing simulations that it can save up to 32% of energy (in average) compared to execution without using any energy-aware algorithm.
BibTeX:
@inproceedings{Nelis2009,
  author = {Nélis, Vincent and Goossens, Joël},
  title = {MORA: an Energy--Aware Slack Reclamation Scheme for Scheduling Sporadic Real-Time Tasks upon Multiprocessor Platforms},
  booktitle = {Proceedings of the 15th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  year = {2009},
  url = {papers/Nelis2009.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2009.30}
}
Nélis, V., Goossens, J. and Andersson, B. Two Protocols for Scheduling Multi--mode Real-Time Systems upon Identical Multiprocessor Platforms 2009 Proceedings of the 21st Euromicro Conference on Real--Time Systems (ECRTS), pp. 151-160  inproceedings DOI URL 
Abstract: We consider the global and preemptive scheduling problem of multi--mode real-time systems upon identical multiprocessor platforms. Since it is a multi-mode system, the system can change from one mode to another such that the current task set is replaced with a new task set. Ensuring that deadlines are met requires not only that a schedulability test is performed on tasks in each mode but also that (i) a protocol for transitioning from one mode to another is specified and (ii) a schedulability test for each transition is performed. We propose two protocols which ensure that all the expected requirements are met during every transition between every pair of operating modes of the system. Moreover, we prove the correctness of our proposed algorithms by extending the theory about the makespan determination problem.
BibTeX:
@inproceedings{Nelis2009a,
  author = {Nélis, Vincent and Goossens, Joël and Andersson, Björn},
  title = {Two Protocols for Scheduling Multi--mode Real-Time Systems upon Identical Multiprocessor Platforms},
  booktitle = {Proceedings of the 21st Euromicro Conference on Real--Time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {151--160},
  url = {papers/Nelis2009a.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2009.27}
}
Nélis, V., Goossens, J., Devillers, R., Milojevic, D. and Navet, N. Power--Aware Real-Time Scheduling upon Identical Multiprocessor Platforms 2008 Proceedings of the 1st IEEE International Conference on Sensor Networks, Ubiquitous, and Trustworthy Computing, pp. 209-216  inproceedings DOI URL 
Abstract: In this paper, we address the power--aware scheduling of sporadic constrained-deadline hard real-time tasks using dynamic voltage scaling upon multiprocessor platforms. We propose two distinct algorithms. Our first algorithm is an off-line speed determination mechanism which provides an identical speed for each processor. That speed guarantees that all deadlines are met if the jobs are scheduled using EDF. The second algorithm is an on-line and adaptive speed adjustment mechanism which reduces the energy consumption while the system is running.
BibTeX:
@inproceedings{Nelis2008,
  author = {Nélis, Vincent and Goossens, Joël and Devillers, Raymond and Milojevic, Dragomir and Navet, Nicolas},
  title = {Power--Aware Real-Time Scheduling upon Identical Multiprocessor Platforms},
  booktitle = {Proceedings of the 1st IEEE International Conference on Sensor Networks, Ubiquitous, and Trustworthy Computing},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {209--216},
  url = {papers/Nelis2008.pdf},
  doi = {http://doi.org/10.1109/SUTC.2008.31}
}
Nélis, V., Marinho, J., Andersson, B. and Petters, S.M. Global-EDF Scheduling of Multimode Real-Time Systems Considering Mode Independent Tasks 2011 Proceedings of the 23rd Euromicro Conference on Real-Time Systems (ECRTS), pp. 205-214  inproceedings DOI URL 
Abstract: Embedded real--time systems often have to support the embedding system in very different and changing application scenarios. An aircraft taxiing, taking off and in cruise flight is one example. The different application scenarios are reflected in the software structure with a changing task set and thus different operational modes. At the same time there is a strong push for integrating previously isolated functionalities in single-chip multicore processors. On such multicores the behavior of the system during a mode change, when the systems transitions from one mode to another, is complex but crucial to get right. In the past we have investigated mode change in multiprocessor systems where a mode change requires a complete change of task set. Now, we present the first analysis which considers mode changes in multicore systems, which use global EDF to schedule a set of mode independent (MI) and mode specific (MS) tasks. In such systems, only the set of MS tasks has to be replaced during mode changes, without jeopardizing the schedulability of the MI tasks. Of prime concern is that the mode change is safe and efficient: i.e. the mode change needs to be performed in a predefined time window and no deadlines may be missed as a function of the mode change.
BibTeX:
@inproceedings{Nelis2011,
  author = {Nélis, Vincent and Marinho, José and Andersson, Björn and Petters, Stefan M.},
  title = {Global-EDF Scheduling of Multimode Real-Time Systems Considering Mode Independent Tasks},
  booktitle = {Proceedings of the 23rd Euromicro Conference on Real-Time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2011},
  pages = {205--214},
  url = {papers/Nelis2011.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2011.27}
}
Nelissen, G. Efficient Optimal Multiprocessor Scheduling Algorithms for Real--Time Systems 2013 School: Université Libre de Bruxelles  phdthesis  
Abstract: Real--time Systems are composed of a set of tasks that must respect some deadlines. We find them in applications as diversified as the telecommunications, medical devices, cars, planes, satellites, military applications, etc. Missing deadlines in a real-time system may cause various results such as a diminution of the quality of service provided by the system, the complete stop of the application or even the death of people. Being able to prove the correct operation of such systems is therefore primordial. This is the goal of the real-time scheduling theory. These last years, we have witnessed a paradigm shift in the computing platform architectures. Uniprocessor platforms have given place to multiprocessor architectures. While the real-time scheduling theory can be considered as being mature for uniprocessor systems, it is still an evolving research field for multiprocessor architectures. One of the main difficulties with multiprocessor platforms, is to provide an optimal scheduling algorithm (i.e., scheduling algorithm that constructs a schedule respecting all the task deadlines for any task set for which a solution exists). Although optimal multiprocessor real-time scheduling algorithms exist, they usually cause an excessive number of task preemptions and migrations during the schedule. These preemptions and migrations cause overheads that must be added to the task execution times. Therefore, task sets that would have been schedulable if preemptions and migrations had no cost, become unschedulable in practice. An efficient scheduling algorithm is therefore an algorithm that either minimize the number of preemptions and migrations, or reduce their cost. In this dissertation, we expose the following results: • We show that reducing the “fairness” in the schedule, advantageously impacts the number of preemptions and migrations. Hence, all the scheduling algorithms that will be proposed in this thesis, tend to reduce or even suppress the fairness in thecomputed schedule. • We propose three new online scheduling algorithms. One of them — namely, BF2 — is optimal for the scheduling of sporadic tasks in discrete-time environments, and reduces the number of task preemptions and migrations in comparison with the state-of-the-art in discrete-time systems. The second one is optimal for the scheduling of periodic tasks in a continuous-time environment. Because this second algorithm is based on a semi-partitioned scheme, it should favorably impact the preemption overheads. The third algorithm — named U-EDF — is optimal for the scheduling of sporadic and dynamic task sets in a continuous-time environment. It is the first real-time scheduling algorithm which is not based on the notion of “fairness” and nevertheless remains optimal for the scheduling of sporadic (and dynamic) systems. This important result was achieved by extending the uniprocessor algorithm EDF to the multiprocessor scheduling problem. • Because the coding techniques are also evolving as the degree of parallelism increases in computing platforms, we provide solutions enabling the scheduling of parallel tasks with the currently existing scheduling algorithms, which were initially designed for the scheduling of sequential independent tasks.
BibTeX:
@phdthesis{Nelissen2013,
  author = {Nelissen, Geoffrey},
  title = {Efficient Optimal Multiprocessor Scheduling Algorithms for Real--Time Systems},
  school = {Université Libre de Bruxelles},
  year = {2013}
}
Nelissen, G., Berten, V., Goossens, J. and Milojevic, D. Optimizing the Number of Processors to Schedule Multi--Threaded Tasks 2011 Proceeding of the Work--in-Progress Session of the 32nd IEEE Real-Time Systems Symposium (WiP RTSS), pp. 5-8  inproceedings URL 
Abstract: In this work we consider the schedule of multithreaded tasks, i.e., each task is a sequence of segments, each segment is a collection of threads, threads of a same segment can be scheduled simultaneously. In this framework we define a technique to optimize the number of processors needed to schedule such sporadic parallel tasks with constrained deadlines. Our offline technique will determine, for each thread, an intermediate deadline to serialize the execution of the segments. Consequently, the online scheduler have to manage sequential constrained deadline sporadic tasks.
BibTeX:
@inproceedings{Nelissen2011,
  author = {Nelissen, Geoffrey and Berten, Vandy and Goossens, Joël and Milojevic, Dragomir},
  title = {Optimizing the Number of Processors to Schedule Multi--Threaded Tasks},
  booktitle = {Proceeding of the Work--in-Progress Session of the 32nd IEEE Real-Time Systems Symposium (WiP RTSS)},
  year = {2011},
  pages = {5--8},
  url = {papers/Nelissen2011.pdf}
}
Nemati, F., Nolte, T. and Behnam, M. Partitioning Real--Time Systems on Multiprocessors with Shared Resources 2010 Proceedings of the 14th International Conference On Principles Of Distributed Systems (OPODIS)  inproceedings DOI URL 
Abstract: In this paper we propose a blocking--aware partitioning algorithm which allocates a task set on a multiprocessor (multi-core) platform in a way that the overall amount of blocking times of tasks are decreased. The algorithm reduces the total utilization which, in turn, has the potential to decrease the total number of required processors (cores). In this paper we evaluate our algorithm and compare it with an existing similar algorithm. The comparison criteria includes both number of schedulable systems as well as processor reduction performance.
BibTeX:
@inproceedings{Nemati2010,
  author = {Nemati, Farhang and Nolte, Thomas and Behnam, Moris},
  title = {Partitioning Real--Time Systems on Multiprocessors with Shared Resources},
  booktitle = {Proceedings of the 14th International Conference On Principles Of Distributed Systems (OPODIS)},
  year = {2010},
  url = {papers/Nemati2010.pdf},
  doi = {http://doi.org/10.1007/978--3-642-17653-1_20}
}
Nguyen, T.H.C. Approximation des temps de réponse des tâches sporadiques à priorité fixe dans les systèmes monoprocesseurs 2010 School: École Nationale Supérieure de Mécanique et d'Aérotechnique  phdthesis URL 
Abstract: Deux techniques sont utilisées pour vérifier que des tâches temps réel respectent bien leurs échéances temporelles : les tests d'ordonnançabilité qui renvoient un résultat binaire (ordonnançable ou non) et les calculs de temps de réponse (Response Time Analysis -- RTA) qui déterminent la longueur du plus long intervalle de temps entre le réveil et la terminaison d'une tâche. Ces deux approches ont une complexité pseudo-polynomiale et notons qu'aucun algorithme polynomial n'est connu. Dans ce contexte, elles ne sont pas particulièrement appropriées pour la conception intéractive des systèmes temps réel ou pour analyser des systèmes distribués à l'aide d'une analyse holistique. Dans de tels scénarios, un algorithme pseudo-polynomial est lent, puisque les calculs des temps de réponse des tâches sont exécutées à de nombreuses reprises. De plus, pour certains systèmes temps réels, tels que dans les systèmes de contrôle-commande, il est nécessaire de connaître le pire temps de réponse des tâches et non seulement la décision binaire sur l'ordonnançabilité des tâches. Dans ce contexte, il peut être acceptable d'utiliser un algorithme plus rapide qui fournit une analyse approchée au lieu d'utiliser des analyses reposant sur des calculs exacts. Comme cette approximation va introduire du pessimisme dans le processus de décision, il est souhaitable de le quantifier d'une manière à définir un compromis entre le temps de calcul et l'exigence de ressource du processeur. C'est la raison pour laquelle, dans ce travail, nous proposons des algorithmes pour calculer efficacement des bornes supérieures des pires temps de réponse et nous présentons des résultats sur leurs qualités dans le pire cas (analyse de compétitivité avec augmentation de ressource) et en moyenne (simulations).
BibTeX:
@phdthesis{Nguyen2010,
  author = {Nguyen, Thi Huyen Chau},
  title = {Approximation des temps de réponse des tâches sporadiques à priorité fixe dans les systèmes monoprocesseurs},
  school = {École Nationale Supérieure de Mécanique et d'Aérotechnique},
  year = {2010},
  url = {papers/Nguyen2010.pdf}
}
de Niz, D., Lakshmanan, K. and Rajkumar, R."R. On the Scheduling of Mixed--Criticality Real-Time Task Sets 2009 Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS), pp. 291-300  inproceedings DOI URL 
Abstract: The functional consolidation induced by the cost reduction trends in embedded systems can force tasks of different criticality (e.g. ABS Brakes with DVD) to share a processor and interfere with each other. These systems are known as mixed criticality systems. While traditional temporal isolation techniques prevent all inter--task interference, they waste utilization because they need to reserve for the absolute worst-case execution time (WCET) for all tasks. In many mixed-criticality systems the WCET is not only rare, but at times difficult to calculate, such as the time to localize all possible objects in an obstacle avoidance algorithm. In this situation it is more appropriate to allow the execution time to grow by stealing cycles from lower-criticality tasks. Even more crucial is the fact that temporal isolation techniques can stop a high-criticality task (that was overrunning its nomimal WCET) to allow a low-criticality task to run, making the former miss its deadline. We identify this as the criticality inversion problem. In this paper, we characterize the criticality inversion problem and present a new scheduling scheme called zero-slack scheduling that implements an alternative protection scheme we refer to as asymmetric protection. This protection only prevents interference from lower-criticality to higher-criticality tasks and improves the schedulable utilization. We use an offline algorithm with two parts: a zero-slack calculation algorithm, and a slack analysis algorithm. The zero-slack calculation algorithm minimizes the utilization needed by a task set by reducing the time low-criticality tasks are preempted by high-criticality ones. This algorithm can be used with priority-based preemptive schedulers (e.g. RMS, EDF). The slack analysis algorithm is specific for each priority-based preemptive scheduler and we develop and evaluated the one for RMS. We prove that this algorithm provides the same level of protection against criticality inversion as the best- known priority assignment for this purpose, criticality as priority assignment (CAPA). We also prove that zero-slack RM provides the same level of schedulable utilization as RMS when all tasks have equal criticality levels. Finally, we present our implementation of the runtime enforcement mechanisms in Linux/RK to demonstrate its practicality.
BibTeX:
@inproceedings{Niz2009,
  author = {de Niz, Dionisio and Lakshmanan, Karthik and Rajkumar, Ragunathan "Raj"},
  title = {On the Scheduling of Mixed--Criticality Real-Time Task Sets},
  booktitle = {Proceedings of the 30th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {291--300},
  url = {papers/Niz2009.pdf},
  doi = {http://doi.org/10.1109/RTSS.2009.46}
}
de Niz, D. and Rajkumar, R."R. Partitioning Bin--Packing Algorithms for Distributed Real-Time Systems 2006 International Journal of Embedded Systems
Vol. 2(3-4), pp. 196-208 
article URL 
Abstract: Embedded real--time systems must satisfy not only logical functional requirements but also para-functional properties such as timeliness, Quality of Service (QoS) and reliability. We have developed a model-based tool called Time Weaver which enables the modeling of functional and para-functional behaviors of real-time systems. It also performs automated schedulability analysis, and generates glue code to integrate the final runtime executable for the system. Its extensive glue code generation capabilities include the ability to insert inter-processor communications code at arbitrary software boundaries. In other words, from a functional point of view, a software component may be viewed as a single logical entity but from the tool point of view, the component can be partitioned into two or more pieces running on different nodes. This capability opens up many different possibilities to map (partitioned) software components to hardware nodes. The objective of this deployment is to minimize hardware requirements while satisfying the timing constraints of the software. The classical approach to addressing this problem is to use bin-packing techniques. In this paper, we study Partitioning Bin Packing, an extension to bin-packing algorithms to exploit the capability of partitioning software modules into smaller pieces. We analytically show that the number of bins required can be reduced. We also evaluate a number of heuristics to minimize not only the number of processors (bins) needed but also the network bandwidth required by communicating software modules that are partitioned across different processors. We find that a significant reduction in the number of bins is possible. Finally, we show how different heuristics lead to different tradeoffs in processing vs network needs.
BibTeX:
@article{Niz2006,
  author = {de Niz, Dionisio and Rajkumar, Ragunathan "Raj"},
  title = {Partitioning Bin--Packing Algorithms for Distributed Real-Time Systems},
  journal = {International Journal of Embedded Systems},
  year = {2006},
  volume = {2},
  number = {3--4},
  pages = {196--208},
  url = {papers/deNiz2006.pdf}
}
Obermaisser, R. Distributed REal--time Architecture for Mixed criticality Systems (DREAMS) 2013 url: http://www.uni--siegen.de/dreams/  electronic URL 
BibTeX:
@electronic{DREAMS,
  author = {Obermaisser, Romain},
  title = {Distributed REal--time Architecture for Mixed criticality Systems (DREAMS)},
  year = {2013},
  url = {http://www.uni--siegen.de/dreams/}
}
Oh, D.-I. and Baker, T.P. Utilization Bounds for N --Processor Rate Monotone Scheduling with Static Processor Assignment 1998 Real--Time Systems
Vol. 15(2), pp. 183-192 
article DOI URL 
Abstract: We consider the schedulability of a set of independent periodic tasks under fixed priority preemptive scheduling on homogeneous multiprocessor systems. Assuming there is no task migration between processors and each processor schedules tasks preemptively according to fixed priorities assigned by the Rate Monotonic policy, the scheduling problem reduces to assigning the set of tasks to disjoint processors in such a way that the Monotonic policy, the scheduling problem reduces to assigning the set of tasks to disjoint processors in such a way that the schedulability of the tasks on each processor can be guaranteed. In this paper we show that the worst case achievable utilization for such systems is between n(2^1/2--1) and (n+1)/(1+2^1/(n+1)), where n stands for the number of processors. The lower bound represents 41 percent of the total system capacity and the upper bound represents 50 to 66 percent depending on n. Practicality of the lower bound is demonstrated by proving it can be achieved using a First Fit scheduling algorithm.
BibTeX:
@article{Oh1998a,
  author = {Oh, Dong--Ik and Baker, Theodore P.},
  title = {Utilization Bounds for N --Processor Rate Monotone Scheduling with Static Processor Assignment},
  journal = {Real--Time Systems},
  year = {1998},
  volume = {15},
  number = {2},
  pages = {183--192},
  url = {papers/Oh1998a.pdf},
  doi = {http://doi.org/10.1023/A:1008098013753}
}
Oh, S.-H. and Yang, S.-M. A Modified Least--Laxity-First scheduling algorithm for real-time tasks 1998 Proceedings of the 6th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 29-36  inproceedings DOI URL 
Abstract: The Least--Laxity-First (LLF) scheduling algorithm assigns higher priority to a task with the least laxity, and has been proved to be optimal for uniprocessor systems. The algorithm, however is impractical to implement because laxity tie results in the frequent context switches among the tasks. The Modified Least-Laxity-First (MLLF) scheduling algorithm proposed in this paper solves the problem of the LLF scheduling algorithm by reducing the number of context switches significantly. By reducing the system overhead due to unnecessary context switches, the MLLF scheduling algorithm avoids the degradation of system performance and conserves more system resources for unanticipated aperiodic tasks. We propose the MLLF scheduling algorithm and prove its optimality. We show the performance enhancement of the proposed MLLF scheduling algorithm by using simulation results.
BibTeX:
@inproceedings{Oh1998,
  author = {Oh, S.--H. and Yang, S.-M.},
  title = {A Modified Least--Laxity-First scheduling algorithm for real-time tasks},
  booktitle = {Proceedings of the 6th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {1998},
  pages = {29--36},
  url = {papers/Oh1998.pdf},
  doi = {http://doi.org/10.1109/RTCSA.1998.726348}
}
Oh, Y. and Son, S.H. Scheduling Real--Time Tasks for Dependability 1997 The Journal of the Operational Research Society
Vol. 46(6), pp. 629-639 
article URL 
Abstract: Real--time systems are increasingly used in applications whose failure may result in large economic and human costs. Since many of the systems operate in environments that are non-deterministic, and even hazardous, it is extremely important that the systems must be dependable, i.e., the deadlines of tasks must be met even in the presence of certain failures. In order to enhance the dependability of a real-time system, we study the problem of scheduling a set of real-time tasks to meet their deadlines even in the presence of processor failures. We first prove that the problem of scheduling a set of non-preemptive tasks on more than two processors to tolerate one arbitrary processor failure is NP-complete even when the tasks share a common deadline. A heuristic algorithm is then proposed to solve the problem. The schedule generated by the heuristic algorithm can tolerate one arbitrary processor failure in the worst case. The analysis and experimental data show that the performance of the heuristic algorithm is near-optimal.
BibTeX:
@article{Oh1997,
  author = {Oh, Yingfeng and Son, Sang H.},
  title = {Scheduling Real--Time Tasks for Dependability},
  journal = {The Journal of the Operational Research Society},
  year = {1997},
  volume = {46},
  number = {6},
  pages = {629--639},
  url = {papers/Oh1997.pdf}
}
Oh, Y. and Son, S.H. Allocating fixed--priority periodic tasks on multiprocessor systems 1995 Real--Time Systems
Vol. 9(3), pp. 207-239 
article DOI  
Abstract: In this paper, we study the problem of allocating a set of periodic tasks on a multiprocessor system such that tasks are scheduled to meet their deadlines on individual processors by the Rate--Monotonic scheduling algorithm. A new schedulability condition is developed for the Rate-Monotonic scheduling that allows us to develop more efficient on-line allocation algorithms. Two on-line allocation algorithms—RM-FF and RM-BF are presented, and shown that their worst-case performance, over the optimal allocation, is upper bounded by 2.33 and lower bounded by 2.28. Then RM-FF and RM-BF are further improved to form two new algorithms: Refined-RM-FF (RRM-FF) and Refined-RM-BF (RRM-BF), both of which have a worst-case performance bound of 2. We also show that when the maximum allowable utilization of a task is small, the worst-case performance of all the new algorithms can be significantly improved. The worst-case performance bounds of RRM-FF and RRM-BF are currently the best bounds in the class of on-line scheduling algorithms proposed to solve the same scheduling problem. Simulation studies show that the average-case performance of the newly proposed algorithms is significantly superior to those in the existing literature.
BibTeX:
@article{Oh1995,
  author = {Oh, Yingfeng and Son, Sang H.},
  title = {Allocating fixed--priority periodic tasks on multiprocessor systems},
  journal = {Real--Time Systems},
  year = {1995},
  volume = {9},
  number = {3},
  pages = {207--239},
  doi = {http://doi.org/10.1007/BF01088806}
}
Oh, Y. and Son, S.H. Fixed--Priority Scheduling of Periodic Tasks on Multiprocessor Systems 1995 (CS-95-16)School: University of Virginia  techreport URL 
Abstract: Consider the problem of periodic task scheduling, in which we seek to minimize the total number of processors required to execute a set of tasks such that task deadlines are guaranteed by the Rate--Monotonic (or RM) algorithm on each processor. This problem was first investigated by Dhall and Liu, and the previous lowest bound for the problem was 2.0. In this paper, an improved solution is given by designing a new algorithm for it. The algorithm, called RM-First-Fit-Decreasing-Utilization (or RM-FFDU), is shown to have a worst-case tight bound of 5/3 = 1.66..., the lowest upper bound ever derived for the scheduling problem. Simulation studies show that on the average, the new algorithm performs consistently better than those in the literature.
BibTeX:
@techreport{Oh1995a,
  author = {Oh, Y. and Son, S. H.},
  title = {Fixed--Priority Scheduling of Periodic Tasks on Multiprocessor Systems},
  school = {University of Virginia},
  year = {1995},
  number = {CS--95-16},
  url = {papers/Oh1995a.pdf}
}
Oh, Y. and Son, S.H. Tight Performance Bounds of Heuristics for a Real--Time Scheduling Problem 1993 (CS-93-24)School: University of Virginia  techreport URL 
Abstract: The problem of scheduling a set of periodic tasks on a number of processors using a fixed--priority assignment scheme was first studied by Dhall and Liu in their paper entitled “On a real-time scheduling problem”. Two scheduling heuristics ¾ Rate-Monotonic-Next-Fit (RMNF) and Rate-Monotonic- First-Fit (RMFF) were proposed, and their worst-case performance was proven to have an upper bound of 2.67 and 2.2, and a lower bound of 2.4 and 2.0, respectively. In this paper, we first tighten up the worst-case bounds for both RMNF and RMFF, and at the same time, correct some errors existing in the original proof of the upper bound for RMFF. The tight worst-cast bounds of RMNF and RMFF are proven to be 2.67 and 2.33, respectively. Then, in an effort to find a more efficient algorithm, we propose a new scheduling heuristic ¾ Rate-Monotonic-Best-Fit (RMBF), and study its worst-case performance. Surprisingly, RMBF also has a tight worst case bound of 2.33.
BibTeX:
@techreport{Oh1993,
  author = {Oh, Yingfeng and Son, Sang H.},
  title = {Tight Performance Bounds of Heuristics for a Real--Time Scheduling Problem},
  school = {University of Virginia},
  year = {1993},
  number = {CS--93-24},
  url = {papers/Oh1993.pdf}
}
Palencia, J. and Gonzalez Harbour, M. Schedulability analysis for tasks with static and dynamic offsets 1998 Proceedings of the 19th IEEE Real--Time Systems Symposium (RTSS), pp. 26-37  inproceedings DOI URL 
Abstract: In this paper we present an extension to current schedulability analysis techniques for periodic tasks with offsets, scheduled under a preemptive fixed priority scheduler. Previous techniques allowed only static offsets restricted to being smaller than the task periods. With the extension presented in this paper, we eliminate this restriction and we allow both static and dynamic offsets. The most significant application of this extension is in the analysis of multiprocessor and distributed systems. We show that we can achieve a significant increase of the maximum schedulable utilization by using the new technique, as opposed to using previously known worst--case analysis techniques for distributed systems.
BibTeX:
@inproceedings{Palencia1998,
  author = {Palencia, J.C. and Gonzalez Harbour, M.},
  title = {Schedulability analysis for tasks with static and dynamic offsets},
  booktitle = {Proceedings of the 19th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1998},
  pages = {26--37},
  url = {papers/Palencia1998.pdf},
  doi = {http://doi.org/10.1109/REAL.1998.739728}
}
Pham, H.-M., Pillement, S. and Piestrak, S.J. Low Overhead Fault--Tolerance Technique for Dynamically Reconfigurable Softcore Processor 2012 IEEE Transactions on Computers
Vol. 99, pp. 15pp 
article DOI URL 
Abstract: In this paper, we propose a new approach to implement a reliable softcore processor on SRAM--based FPGAs, which can mitigate radiation-induced temporary faults (single-event upsets (SEUs)) at moderate cost. A new Enhanced Lockstep scheme built using a pair of MicroBlaze cores is proposed and implemented on Xilinx Virtex-5 FPGA. Unlike the basic lockstep scheme, ours allows to detect and eliminate its internal temporary configuration upsets without interrupting normal functioning. Faults are detected and eliminated using a Configuration Engine built on the basis of the PicoBlaze core which, to avoid a single point of failure, is implemented as fault-tolerant using triple modular redundancy (TMR). A softcore processor can recover from configuration upsets through partial reconfiguration combined with roll-forward recovery. SEUs affecting logic which are significantly less likely than those affecting configuration are handled by checkpointing and rollback. Finally, to handle permanent faults, the tiling technique is also proposed. The new Enhanced Lockstep scheme requires significantly shorter error recovery time compared to conventional lockstep scheme and uses significantly smaller number of slices compared to known TMR-based design (although at the cost of longer error recovery time). The efficiency of the proposed approach was validated through fault injection experiments.
BibTeX:
@article{Pham2012,
  author = {Pham, Hung--Manh and Pillement, Sébastien and Piestrak, Stanisław J.},
  title = {Low Overhead Fault--Tolerance Technique for Dynamically Reconfigurable Softcore Processor},
  journal = {IEEE Transactions on Computers},
  year = {2012},
  volume = {99},
  pages = {15pp},
  url = {papers/Pham2012.pdf},
  doi = {http://doi.org/10.1109/TC.2012.55}
}
Piao, X., Han, S., Kim, H., Park, M., Cho, Y. and Cho, S. Predictability of Earliest Deadline Zero Laxity Algorithm for Multiprocessor Real--Time Systems 2006 Proceedings of 9th International Symposium on Object/Component/Service--Oriented Real-Time Distributed Computing (ISORC), pp. 6 pp.  inproceedings DOI URL 
Abstract: Validation methods for hard real--time jobs are usually performed based on the maximum execution time. The actual execution time of jobs are assumed to be known only when the jobs arrive or not known until they finish. A predictable algorithm must guarantee that it can generate a schedule for any set of jobs such that the finish time for the actual execution time is no later than the finish time for the maximum execution time. It is known that any job-level fixed priority algorithm (such as earliest deadline first) is predictable. However, job-level dynamic priority algorithms (such as least laxity first) may or may not. In this paper, we investigate the predictability of a job-level dynamic priority algorithm EDZL (earliest deadline zero laxity). We show that EDZL is predictable on the domain of integers regardless of the knowledge of the actual execution times. Based on this result, furthermore, we also show that EDZL can successfully schedule any periodic task set if the total utilization is not greater than (m + 1)/2, where m is the number of processors.
BibTeX:
@inproceedings{Piao2006,
  author = {Piao, Xuefeng and Han, Sangchul and Kim, Heeheon and Park, Minkyu and Cho, Yookun and Cho, Seongje},
  title = {Predictability of Earliest Deadline Zero Laxity Algorithm for Multiprocessor Real--Time Systems},
  booktitle = {Proceedings of 9th International Symposium on Object/Component/Service--Oriented Real-Time Distributed Computing (ISORC)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {6 pp.},
  url = {papers/Piao2006.pdf},
  doi = {http://doi.org/10.1109/ISORC.2006.64}
}
Pillement, S., Sentieys, O. and David, R. DART: A Functional--Level Reconfigurable Architecture for High Energy Efficiency 2008 EURASIP Journal on Embedded Systems (JES)
Vol. 2008, pp. 13 
article DOI URL 
Abstract: Flexibility becomes a major concern for the development of multimedia and mobile communication systems, as well as classical high--performance and low-energy consumption constraints. The use of general-purpose processors solves flexibility problems but fails to cope with the increasing demand for energy efficiency. This paper presents the DART architecture based on the functional-level reconfiguration paradigm which allows a significant improvement in energy efficiency. DART is built around a hierarchical interconnection network allowing high flexibility while keeping the power overhead low. To enable specific optimizations, DART supports two modes of reconfiguration. The compilation framework is built using compilation and high-level synthesis techniques. A 3G mobile communication application has been implemented as a proof of concept. The energy distribution within the architecture and the physical implementation are also discussed. Finally, the VLSI design of a 0.13 µm CMOS SoC implementing a specialized DART cluster is presented.
BibTeX:
@article{Pillement2008,
  author = {Pillement, Sébastien and Sentieys, Olivier and David, Raphaël},
  title = {DART: A Functional--Level Reconfigurable Architecture for High Energy Efficiency},
  journal = {EURASIP Journal on Embedded Systems (JES)},
  year = {2008},
  volume = {2008},
  pages = {13},
  url = {papers/Pillement2008.pdf},
  doi = {http://doi.org/10.1155/2008/562326}
}
Pineau, J.-F., Robert, Y. and Vivien, F. Energy--aware scheduling of bag-of-tasks applications on master–worker platforms 2011 Concurrency and Computation: Practice and Experience
Vol. 23(2), pp. 145-157 
article DOI URL 
Abstract: We consider the problem of scheduling an application composed of independent tasks on a fully heterogeneous master–worker platform with communication costs. We introduce a bi--criteria approach aiming at maximizing the throughput of the application while minimizing the energy consumed by participating resources. Assuming arbitrary super-linear power consumption laws, we investigate different models, with energy overheads and memory constraints. Building upon closed-form expressions for the uni-processor case, we derive asymptotically optimal solutions for all models.
BibTeX:
@article{Pineau2011,
  author = {Pineau, Jean--François and Robert, Yves and Vivien, Frédéric},
  title = {Energy--aware scheduling of bag-of-tasks applications on master–worker platforms},
  journal = {Concurrency and Computation: Practice and Experience},
  year = {2011},
  volume = {23},
  number = {2},
  pages = {145--157},
  url = {papers/Pineau2011.pdf},
  doi = {http://doi.org/10.1002/cpe.1634}
}
Pitter, C. and Schoeberl, M. Towards a Java Multiprocessor 2007 Proceedings of the 5th international workshop on Java Technologies for Real--Time and Embedded Systems (JTRES), pp. 144-151  inproceedings DOI URL 
Abstract: This paper describes the first steps towards a Java multiprocessor system on a single chip for embedded systems. The chip multiprocessing (CMP) system consists of a homogeneous set of processing elements and a shared memory. Each processor core is based on the Java Optimized Processor (JOP). A major challenge in CMP is the shared memory access of multiple CPUs. The proposed memory arbiter resolves possible emerging conflicts of parallel accesses to the shared memory using a fixed priority scheme. Furthermore, the paper describes the boot--up of the CMP. We verify the proposed CMP architecture by the implementation of the prototype called JopCMP. JopCMP consists of multiple JOPs and a shared memory. Finally yet importantly, the first implementation of the CMP composed of two/three JOPs in an FPGA enables us to present a comparison of the performance between a single-core JOP and the CMP version by running real applications.
BibTeX:
@inproceedings{Pitter2007,
  author = {Pitter, Christoph and Schoeberl, Martin},
  title = {Towards a Java Multiprocessor},
  booktitle = {Proceedings of the 5th international workshop on Java Technologies for Real--Time and Embedded Systems (JTRES)},
  publisher = {ACM},
  year = {2007},
  pages = {144--151},
  url = {papers/Pitter2007.pdf},
  doi = {http://doi.org/10.1145/1288940.1288962}
}
Pree, W. and Templ, J. Modeling with the Timing Definition Language (TDL) 2008
Vol. 4922, pp. 133-144 
incollection DOI URL 
Abstract: This paper describes the model--based development process of hard real-time software with the Timing Definition Language (TDL): modeling and simulation of TDL components in Matlab®/Simulink®, their mapping to a specific platform and finally the code generation.
BibTeX:
@incollection{Pree2008,
  author = {Pree, Wolfgang and Templ, Josef},
  title = {Modeling with the Timing Definition Language (TDL)},
  publisher = {Springer Berlin / Heidelberg},
  year = {2008},
  volume = {4922},
  pages = {133--144},
  url = {papers/Pree2008.pdf},
  doi = {http://doi.org/10.1007/978--3-540-70930-5_9}
}
Puaut, I. and Decotigny, D. Low--Complexity Algorithms for Static Cache Locking in Multitasking Hard Real-Time Systems 2002 Proceedings of the 23rd IEEE Real--Time Systems Symposium (RTSS), pp. 114-123  inproceedings DOI  
Abstract: Cache memories have been extensively used to bridge the gap between high speed processors and relatively slow main memories. However, they are a source of predictability problems because of their dynamic and adaptive behavior and thus need special attention to be used in hard--real time systems. A lot of progress has been achieved in the last ten years to statically predict the worst-case behavior of applications with respect to caches in order to determine safe and precise bounds on task worst-case execution times (WCETs) and cache-related preemption delays. An alternative approach to cope with caches in real-time systems is to statically lock their contents such that memory access times and cache-related preemption times are predictable. In this paper, we propose two low-complexity algorithms for selecting the contents of statically-locked caches. We evaluate their performances and compare them with those of a state of the art static cache analysis method.
BibTeX:
@inproceedings{Puaut2002,
  author = {Puaut, Isabelle and Decotigny, David},
  title = {Low--Complexity Algorithms for Static Cache Locking in Multitasking Hard Real-Time Systems},
  booktitle = {Proceedings of the 23rd IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2002},
  pages = {114--123},
  doi = {http://doi.org/10.1109/REAL.2002.1181567}
}
Punnekkat, S. Schedulability Analysis for Fault Tolerant Real--Time Systems 1997 School: University of York  phdthesis URL 
Abstract: Predictability and fault tolerance are major requirements for complex real--time systems, which are either safety or mission critical. Traditionally fault tolerant techniques were employed to tackle the problem of ensuring correctness in the value domain only. We stress that the fault tolerance requirements and timing constraints are not orthogonal issues as they appear to be, and hence any viable approach must be an integrated one. Fault tolerance in a real-time system implies that the system is able to deliver correct results in a timely manner even in the presence of faults. Techniques employing time redundancy are commonly used for tolerating a wide class of faults such as transient faults. In these systems, it is essential that the exploitation of time redundancy for correctness does not jeopardize the timeliness attribute. Hence scheduling aspects of fault tolerant real-time systems become all the more important. The research work described in this thesis, focuses on the provision of tests for the feasibility analysis of fault tolerant task sets. These feasibility tests are based on fixed priority scheduling theory, and are formulated under various assumptions regarding frequency of fault occurrences and fault recovery strategy. We have analysed the effects of checkpointing schemes with respect to schedulability. Another important issue we addressed is the estimation of the system’s tolerance to perturbations in its timing parameters. Finally, we provide the notion of probabilistic guarantees to account for nondeterminisms. This complementary approach to the normal deterministic analysis of real-time systems, is an effort towards integrating scheduling theory and probabilistic fault models. The results presented in this thesis provide a foundation for employing fixed priority scheduling theory in the analysis of fault tolerant real-time systems. We expect these results will aid the system designers in the development of predictable and fault tolerant real-time systems.
BibTeX:
@phdthesis{Punnekkat1997,
  author = {Punnekkat, Sasikumar},
  title = {Schedulability Analysis for Fault Tolerant Real--Time Systems},
  school = {University of York},
  year = {1997},
  url = {papers/Punnekkat1997.pdf}
}
Punnekkat, S., Davis, R.I. and Alan, B. Sensitivity Analysis of Real--Time Task Sets 1997
Vol. 1345Proceedings of the 3rd Asian Computing Science Conference (ASIAN), pp. 72-82 
inproceedings DOI URL 
Abstract: Though schedulability analysis has matured to the point where it is now possible to analyse realistic systems, there is still a lack of flexibility as far as the designer is concerned. Feasibility tests often provide little or no indication of the changes in task timing characteristics required to achieve a feasible system, nor any indication of the extent to which the worst case execution times of tasks may be increased without causing deadlines to be missed (in the case of a feasible system). In practice, however, it is useful to know how sensitive system feasibility is to changes in task timing characteristics. We give a general approach to the sensitivity analysis of task sets, which aids system developers in incorporating changes to the system whilst ensuring that the schedulability guarantees remain intact.
BibTeX:
@inproceedings{Punnekkat1997a,
  author = {Punnekkat, Sasikumar and Davis, Robert Ian and Burns Alan},
  title = {Sensitivity Analysis of Real--Time Task Sets},
  booktitle = {Proceedings of the 3rd Asian Computing Science Conference (ASIAN)},
  publisher = {Springer Berlin / Heidelberg},
  year = {1997},
  volume = {1345},
  pages = {72--82},
  url = {papers/Punnekkat1997a.pdf},
  doi = {http://doi.org/10.1007/3--540-63875-X_44}
}
Qamhieh, M., Fauberteau, F., George, L. and Midonnet, S. Global EDF Scheduling of Directed Acyclic Graphs on GEDF Scheduling Multiprocessor Systems 2013 Proceeding of the 21st International Conference on Real--Time and Network Systems (RTNS), pp. 287-296  inproceedings DOI  
Abstract: In this paper, we study the problem of real--time scheduling of parallel tasks represented by a Directed Acyclic Graph (DAG) on multiprocessor architectures. We focus on Global Earliest Deadline First scheduling of sporadic DAG tasksets with constrained-deadlines on a system of homogeneous processors. Our contributions consist in analyzing DAG tasks by considering their internal structures and providing a tighter bound on the workload and interference analysis. This approach consists in assigning a local offset and deadline for each subtask in the DAG. We derive an improved sufficient schedulability test w.r.t. an existing test proposed in the state of the art. Then we discuss the sustainability of this test.
BibTeX:
@inproceedings{Qamhieh2013,
  author = {Qamhieh, Manar and Fauberteau, Frédéric and George, Laurent and Midonnet, Serge},
  title = {Global EDF Scheduling of Directed Acyclic Graphs on GEDF Scheduling Multiprocessor Systems},
  booktitle = {Proceeding of the 21st International Conference on Real--Time and Network Systems (RTNS)},
  publisher = {ACM},
  year = {2013},
  pages = {287--296},
  doi = {http://doi.org/10.1145/2516821.2516836}
}
Qamhieh, M., Fauberteau, F. and Midonnet, S. Performance Analysis for Segment Stretch Transformation of Parallel Real--time Tasks 2011 Proceedings of the 2th Junior Researcher Workshop on Real--Time Computing (JRWRTC), pp. 4pp  inproceedings URL 
Abstract: The Segment Stretch Transformation (SST) is an algorithm that transforms parallel Fork--Join (FJ) tasks into sequential tasks on multiprocessor systems when possible. SST is based on Task Stretch Transformation (TST) which is a transformation for the same model of tasks, but it uses segment migrations while SST eliminates their use. In this paper, we prove that both transformations have the same performance by providing a detailed analysis based on Demand Bound Function (DBF) and by showing that SST has a resource augmentation bound of 3.42, same as TST, which means that if a taskset is feasible on m speed processors, then it is schedulable using the transformation on m processors that are 3.42 times faster.
BibTeX:
@inproceedings{Qamhieh2011,
  author = {Qamhieh, Manar and Fauberteau, Frédéric and Midonnet, Serge},
  title = {Performance Analysis for Segment Stretch Transformation of Parallel Real--time Tasks},
  booktitle = {Proceedings of the 2th Junior Researcher Workshop on Real--Time Computing (JRWRTC)},
  year = {2011},
  pages = {4pp},
  url = {papers/Qamhieh2011.pdf}
}
Qin, X. and Jiang, H. A novel fault--tolerant scheduling algorithm for precedence constrained tasks in real-time heterogeneous systems 2006 Parallel Computing
Vol. 32(5-6), pp. 331-356 
article DOI URL 
Abstract: Fault--tolerance is an essential requirement for real-time systems, due to potentially catastrophic consequences of faults. In this paper, we investigate an efficient off-line scheduling algorithm generating schedules in which real-time tasks with precedence constraints can tolerate one processor’s permanent failure in a heterogeneous system with fully connected network. The tasks are assumed to be non-preemptable, and each task has two copies scheduled on different processors and mutually excluded in time. In the literature in recent years, the quality of a schedule has been previously improved by allowing a backup copy to overlap with other backup copies on the same processor. However, this approach assumes that tasks are independent of one other. To meet the needs of real-time systems where tasks have precedence constraints, a new overlapping scheme is proposed. We show that, given two tasks, the necessary conditions for their backup copies to safely overlap in time with each other are (1) their corresponding primary copies are scheduled on two different processors, (2) they are independent tasks, and (3) the execution of their backup copies implies the failures of the processors on which their primary copies are scheduled. For tasks with precedence constraints, the new overlapping scheme allows the backup copy of a task to overlap with its successors’ primary copies, thereby further reducing schedule length. Based on a proposed reliability model, tasks are judiciously allocated to processors so as to maximize the reliability of heterogeneous systems. Additionally, times for detecting and handling of a permanent fault are incorporated into the scheduling scheme. We have performed experiments using synthetic workloads as well as a real world application. Simulation results show that compared with existing scheduling algorithms in the literature, our scheduling algorithm improves reliability by up to 22.4% (with an average of 16.4 and achieves an improvement in performability, a measure that combines reliability and schedulability, by up to 421.9% (with an average of 49.3.
BibTeX:
@article{Qin2006,
  author = {Qin, Xiao and Jiang, Hong},
  title = {A novel fault--tolerant scheduling algorithm for precedence constrained tasks in real-time heterogeneous systems},
  journal = {Parallel Computing},
  year = {2006},
  volume = {32},
  number = {5--6},
  pages = {331--356},
  url = {papers/Qin2006.pdf},
  doi = {http://doi.org/10.1016/j.parco.2006.06.006}
}
Qin, X. and Jiang, H. Dynamic, reliability--driven scheduling of parallel real-time jobs in heterogeneous systems 2001 Proceedings of the International Conference on Parallel Processing (ICPP), pp. 113-122  inproceedings DOI URL 
Abstract: In this paper, a heuristic dynamic scheduling scheme for parallel real--time jobs in a heterogeneous system is presented. The parallel real-time jobs studied in this paper are modelled by directed acyclic graphs (DAG). We assume a scheduling environment where parallel real-time jobs arrive at a heterogeneous system following a Poisson process. The scheduling algorithms developed in this paper take the reliability measure into account, in order to enhance the reliability of the heterogeneous system without any additional hardware cost. In addition, scheduling time and dispatch time are both incorporated into our scheduling scheme so as to make the scheduling result more realistic and precise. Admission control is in place so that a parallel real-time job whose deadline cannot be guaranteed is rejected by the system. The performance of the proposed scheme is evaluated via extensive simulations. The simulation results show that the heuristic algorithm performs significantly better than two other algorithms that do not consider reliability cost. Furthermore, results suggest that shortening the scheduling time results in a higher guarantee ratio. Hence, if parallel scheduling algorithm is devised and employed to shorten the scheduling time, the performance of the heterogeneous system will be further enhanced.
BibTeX:
@inproceedings{Qin2001,
  author = {Qin, Xiao and Jiang, Hong},
  title = {Dynamic, reliability--driven scheduling of parallel real-time jobs in heterogeneous systems},
  booktitle = {Proceedings of the International Conference on Parallel Processing (ICPP)},
  publisher = {IEEE Computer Society},
  year = {2001},
  pages = {113--122},
  url = {papers/Qin2001.pdf},
  doi = {http://doi.org/10.1109/ICPP.2001.952053}
}
Rahni, A. Contributions à la validation d'ordonnancement temps réel en présence de transactions sous priorités fixes et EDF 2008 School: Université de Poitiers  phdthesis URL 
Abstract: L’informatique temps réel est largement utilisée et prend une importance de plus en plus grande dans la vie quotidienne. Plusieurs domaines d’application sont concernés, notamment, l’automobile, l’avionique, la téléphonie mobile, le multimédia, l’énergie, ...etc. Les systèmes temps réel concernent des applications informatiques ayant un rôle de suivi ou de contrôle de procédé dans un environnement qui évolue dynamiquement. L’application est réactive, en effet, elle doit réagir au changement d’état du système contrôlé dans des contraintes temporelles précises. D’où le bon fonctionnement d’un système temps réel ne dépend pas seulement de l’exactitude des résultats du calcul mais aussi des dates auxquelles ces résultats sont produits. Certains systèmes sont classés critiques lorsque le non respect des contraintes temporelles peut provoquer des conséquences catastrophiques (perte de vies humaines, destruction de matériel, ...). Les systèmes de contrôle de vol, systèmes de contrôle de centrale nucléaire en sont des exemples.
Généralement, un système temps réel est composé d’un ensemble de tâches exécutées en concurrence pour utiliser le (ou les) processeur et certaines ressources partagées. Le plus souvent les exigences temporelles sont reportées sur les échéances d’exécution des tâches. Par conséquent, une validation temporelle consiste de vérifier que toutes les tâches d’un système terminent leur exécution avant leurs échéances, durant toute la vie du système, et cela en examinant le pire scénario d’exécution de tâches, s’il existe un moyen de la garantir alors le système est dit ordonnançable. Le test d’ordonnançabilité est dépendant du modèle de tâches qui définit l’ensemble des restrictions auxquelles doivent se conformer les tâches et de l’algorithme d’ordonnancement utilisé pour déterminer l’ordre dans lequel doivent être exécutées les tâches. L’un des principaux problèmes du test d’ordonnançabilité est l’identification du pire scénario d’exécution des tâches et la complexité de l’analyse.
L’objectif de cette thèse est d’introduire de nouveaux tests d’ordonnançabilité et d’optimiser leur qualité de réponse et leur temps de calcul pour le modèle de tâches avec décalages d’activations (appelé transactions), dans les deux contextes d’ordonnancement : en priorités fixes et en priorités dynamiques EDF.
Dans le chapitre 1, nous exposons le problème de l’ordonnancement, après avoir présenté brièvement l’architecture logicielle et matérielle des systèmes temps réel et les différents facteurs définissant le contexte d’ordonnancement de tâches. Puis nous présentons les différentes techniques d’analyse d’ordonnançabilité. Les résultats d’analyse d’ordonnançabilité des tâches périodiques et sporadiques, basées sur le modèle de Liu et Layland, seront présentés. Ces résultats seront classés par technique d’analyse (analyse de facteur d’utilisation, de temps de réponse ou de la demande processeur) et par algorithme d’ordonnancement (priorités fixes ou priorités dynamiques).
Les conditions d’ordonnançabilité présentées dans le chapitre 1 sont pessimistes pour certains types d’application car le modèle de tâches considéré ne modélise pas finement leur comportement. Plusieurs modèles de tâches sont spécifiques aux types d’applications où un décalage d’activation entre les tâches est prise en considération. Nous commençons, dans le chapitre 2, par présenter le modèle de tâches à offsets (transactions temps réel), puis nous présentons le test d’ordonnançabilité par l’analyse de temps de réponse. En priorités dynamiques, comme en priorités fixes, l’analyse exacte a une complexité exponentielle due au nombre de scénarios à étudier, et seulement des méthodes d’analyse approchées (et donc pessimistes) avec une complexité pseudo--polynomiale sont proposées. D’où la problématique du test d’ordonnançabilité des systèmes de transactions. Les mêmes problèmes sont recensés dans l’analyse des tâches multiframes qui est présentée à la fin du chapitre 2.
Dans la partie contribution, nous montrons, dans un premier temps, que les transactions sont le modèle le plus général dans tous les modèles présentés précédemment (en particulier les tâches multiframes) i.e. tout résultat valable pour les transactions est valable pour les tâches multiframes. Le chapitre 3 présente une nouvelle méthode d’analyse mixte de temps de réponse, avec une complexité pseudo--polynomiale, des tâches à offset avec priorités fixes. Notre idée est de combiner l’analyse exacte d’interférence pour certaines transactions avec l’analyse approchée pour les autres transactions. Cette méthode fournit un temps de réponse meilleur (mais pessimiste) que celui fourni par les méthodes d’analyse approchées. Comme nous montrons dans l’évaluation de performance, plus le nombre de transactions pour lesquelles une analyse exacte d’interférence est appliquée, meilleure est la qualité de la réponse, mais cet avantage est limité par le temps de calcul. Cependant, la méthode mixte avec une analyse exacte d’interférence pour deux transactions fournit le meilleur compromis entre qualité et temps de calcul.
Le chapitre 4 focalise sur le problème d’identification de pire scénario, en priorités fixes. Un instant critique (pire scénario) se produit lorsqu’une tâche de chaque transaction s’active simultanément. Malheureusement, nous ne savons pas quelle tâche candidate dans chaque transaction initie l’instant critique, d’où la nécessité d’étudier toutes les combinaisons possibles entre les tâches des transactions. Dans un premier temps nous étudions et montrons les limites des transactions monotoniques (sans gigue). Ce sont des transactions respectant une structure particulière, où la tâche initiant l’instant critique est connue. Ensuite, nous définissons une propriété d’accumulativité monotonique permettant d’identifier toutes les transactions (avec et sans gigues) pour lesquelles la tâche initiant l’instant critique pourra être connue. Cette propriété, comme nous le montrons dans l’évaluation de performances, minimise significativement le nombre de scénarios à étudier ainsi que le temps de calcul, et fournit des temps de réponse exacts lorsque l’accumulativité monotonique est satisfaite par toutes les transactions du système. Nous proposons, dans le cas des transactions non accumulativement monotoniques, une propriété, celle de dominance de tâche, permettant d’éviter l’étude des scénarios définis par des tâches dominées et ainsi améliorer le temps de calcul.
Le chapitre 5 est consacré à l’analyse d’ordonnançabilité des transactions ordonnancées par EDF. Seule un test exact avec une complexité exponentielle était connu. Les tests pseudo--polynomiaux étaient approchés. Ces résultats sont basés sur l’analyse de temps de réponse. Nous proposons dans ce chapitre un test d’ordonnançabilité exact avec une complexité pseudo-polynomiale, ce test est basé sur l’analyse de la demande processeur. Le principe est de prouver que pour tout intervalle de temps de longueur t, la demande processeur du système est inférieure ou égale à t. Finalement, quelques conclusions autour des résultats majeurs présentés dans ce document et des perspectives sont données.
BibTeX:
@phdthesis{Rahni2008,
  author = {Rahni, Ahmed},
  title = {Contributions à la validation d'ordonnancement temps réel en présence de transactions sous priorités fixes et EDF},
  school = {Université de Poitiers},
  year = {2008},
  url = {papers/Rahni2008.pdf}
}
Rahni, A., Grolleau, E., Richard, M. and Richard, P. Feasibility analysis of real-time transactions 2012 Real-Time Systems
Vol. 48(3), pp. 320-358 
article DOI URL 
Abstract: The objective of this paper is two-fold: give a survey of response time analysis (RTA), and contribute to schedulability analysis for the real-time transaction model. The RTA is studied under fixed priority policies (FPP), while schedulability analysis assumes an optimal scheduling algorithm (like the deadline driven scheduling algorithm EDF) in a preemptive context on uniprocessor systems. We compare the transaction model to the family of multiframe models, then present the exact, and approximated methods, as well as a tunable method to compute the RTA. Finally we present a new schedulability analysis method and an efficient algorithm to speed up this test.
BibTeX:
@article{Rahni2012,
  author = {Rahni, Ahmed and Grolleau, Emmanuel and Richard, Mickaël and Richard, Pascal},
  title = {Feasibility analysis of real-time transactions},
  journal = {Real-Time Systems},
  year = {2012},
  volume = {48},
  number = {3},
  pages = {320--358},
  url = {papers/Rahni2012.pdf},
  doi = {http://doi.org/10.1007/s11241-012-9147-z}
}
Rajkumar, R."R. Synchronization in Real--Time Systems: A Priority Inheritance Approach 1991 , pp. 195  book  
BibTeX:
@book{Rajkumar1991,
  author = {Rajkumar, Ragunathan "Raj"},
  title = {Synchronization in Real--Time Systems: A Priority Inheritance Approach},
  publisher = {Kluwer Academic Publishers},
  year = {1991},
  pages = {195}
}
Rajkumar, R."R. Real--time synchronization protocols for shared memory multiprocessors 1990 Proceedings of the 10th International Conference on Distributed Computing Systems (ICDCS), pp. 116-123  inproceedings DOI URL 
Abstract: Multiprocessors have become popular in recent years due to hardware trends towards increasing performance with multiple processing elements. The speedups possible in multiprocessors are particularly attractive for real--time systems where additional computing power is in general desirable. Variouv synchronization mechanism have been proposed and implemented in shared memory multiprocessors to synchronize tasks running on different processors. In hard real-time systems, any delays due to synchronization requirements must be bounded. Unfortunately, a direct use of common primitives like shared memory semaphores and message-based rendez-vous in multiprocessors may cause a task to be blocked for an arbitrary duration of time. A multiprocessor protocol that bound blocking duration on shared resources has been defined in [8]. Under this protocol, any given globally shared resource is controlled from a designated processor. This protocol is particularly well-suited for message-passing architectures, but does not exploit the availability of globally accessible shared memory in tightly coupled multiprocessors. In this paper, we define and analyze a priority-based synchronization protocol that explicitly uses shared memory primitives.
BibTeX:
@inproceedings{Rajkumar1990,
  author = {Rajkumar, Ragunathan "Raj"},
  title = {Real--time synchronization protocols for shared memory multiprocessors},
  booktitle = {Proceedings of the 10th International Conference on Distributed Computing Systems (ICDCS)},
  publisher = {IEEE Computer Society},
  year = {1990},
  pages = {116--123},
  url = {papers/Rajkumar1990.pdf},
  doi = {http://doi.org/10.1109/ICDCS.1990.89257}
}
Rajkumar, R."R., Sha, L. and Lehoczky, J.P. Real--time synchronization protocols for multiprocessors 1988 Proceedings of the 9th IEEE Real--Time Systems Symposium (RTSS), pp. 259-269  inproceedings DOI URL 
Abstract: The potential speedup of applications has motivated the widespread use of multiprocessors in recent years. Several mechanisms exist to synchronize tasks that execute on different processors, but share dota and resources. In a hard real--time context, however, these synchronization mechanisms need to have bounded the blocking duration of a task waiting for a resource. Only then can deadlines of tasks can be guaranteed. Unfortunately, a direct application of commonly used synchronization primitives like semaphores, monitors or message-passing mechanisms such as the Ada rendezvous can lead to uncontrolled priority inversion where a higher priority task is blocked by a lower priority task for an indefinite period of time. This paper studies the class of priority inheritance protocols for synchronizing tasks executing in parallel on multiprocessors. The multiprocessor priority ceiling protocol is a priority inheritance protocol that not only bounds the duration of blocking but also prevents deadlocks. These properties allow us to derive a set of sufficient conditions under which a set of periodic tasks using this protocol will be schedulable.
BibTeX:
@inproceedings{Rajkumar1988,
  author = {Rajkumar, Ragunathan "Raj" and Sha, Lui and Lehoczky, John P.},
  title = {Real--time synchronization protocols for multiprocessors},
  booktitle = {Proceedings of the 9th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1988},
  pages = {259--269},
  url = {papers/Rajkumar1988.pdf},
  doi = {http://doi.org/10.1109/REAL.1988.51121}
}
Ramos-Thuel, S. and Lehoczky, J.P. On-Line Scheduling of Hard Deadline Aperiodic Tasks in Fixed-Priority Systems 1993 Proceedings of the 14th IEEE Real-Time Systems Symposium (RTSS), pp. 160-171  inproceedings DOI URL 
Abstract: This paper presents a new algorithm for the on--line scheduling of hard deadline aperiodic tasks in a realtime system in which hard deadline periodic tasks are scheduled using a fized priority algorithm. The algorithm for jointly scheduling the periodic and aperiodic tasks eztends the slack stealing algorithm introduced by Lehoczky and Ramos-Thuel, and thus provides the largest amount of time for aperiodic task processing subject to meeting all periodic task deadlines. The analysis permits the periodic tasks to consist of a set of serially executed subtasks each of which has its own fized ezecution priority as defined by Gonzalez Harbour et. al.. Thus the model permits ihe direct inclusion of operating system functions as well as certain types of synchronization protocols directly into ihe schedulability analysis. The methods provide a unified framework for dealing with several related problems including: reclaiming unused periodic and aperiodic execution time, load shedding, balancing hard and soft aperiodic ezecution time and coping with transient overloads.
BibTeX:
@inproceedings{Ramos--Thuel1993,
  author = {Ramos-Thuel, Sandra and Lehoczky, John P.},
  title = {On-Line Scheduling of Hard Deadline Aperiodic Tasks in Fixed-Priority Systems},
  booktitle = {Proceedings of the 14th IEEE Real-Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1993},
  pages = {160--171},
  url = {papers/Ramos-Thuel1993.pdf},
  doi = {http://doi.org/10.1109/REAL.1993.393504}
}
Raravi, G. and Nélis, V. A PTAS for assigning sporadic tasks on two--type heterogeneous multiprocessors 2012 (HURRAY-TR-120505)School: Polytechnic Institute of Porto (ISEP--IPP)  techreport URL 
Abstract: Consider the problem of determining a task--to-processor assignment for a given collection of implicit-deadline sporadic tasks upon a multiprocessor platform in which there are two distinct kinds of processors. We propose a polynomial-time approximation scheme (PTAS) for this problem. It offers the following guarantee: for a given task set and a given platform, if there exists a feasible task-to-processor assignment, then given an input parameter, 'e', our PTAS succeeds, in polynomial time, in finding such a feasible task-to-processor assignment on a platform in which each processor is 1+3e times faster. In the simulations, our PTAS outperforms the state-of-the-art PTAS and also for the vast majority of task sets, it requires significantly smaller processor speedup than (its upper bound of) 1+3e for successfully determining a feasible task-to-processor assignment.
BibTeX:
@techreport{Raravi2012,
  author = {Raravi, Gurulingesh and Nélis, Vincent},
  title = {A PTAS for assigning sporadic tasks on two--type heterogeneous multiprocessors},
  school = {Polytechnic Institute of Porto (ISEP--IPP)},
  year = {2012},
  number = {HURRAY--TR-120505},
  url = {papers/Raravi2012.pdf}
}
Real, J. and Crespo, A. Mode Change Protocols for Real--Time Systems: A Survey and a New Proposal 2004 Real-Time Systems
Vol. 26(2), pp. 161-197 
article DOI URL 
Abstract: This paper contains both a survey of mode change protocols for single--processor, fixed-priority, preemptively scheduled real-time systems, and a proposal of several new protocols along with their corresponding schedulability analysis and configuration methods. First, a classification of the protocols found in the literature is given and a set of requirements is proposed for their evaluation. Then, the new protocols are introduced and discussed in the light of the stated requirements. A number of mode change protocols are based on delaying the initiation of the new mode by applying an offset to the initial release of tasks in the destination mode. We tackle the problem of how to obtain these offsets for the proposed protocols. The issue of consistently sharing resources during the mode change by means of a priority inheritance protocol is also dealt with.
BibTeX:
@article{Real2004,
  author = {Real, Jorge and Crespo, Alfons},
  title = {Mode Change Protocols for Real--Time Systems: A Survey and a New Proposal},
  journal = {Real-Time Systems},
  year = {2004},
  volume = {26},
  number = {2},
  pages = {161--197},
  url = {Response time analysisProcessor demandReal-time transactionsTasks with offsetsFixed Priority PolicyDeadline Driven Scheduling},
  doi = {http://doi.org/10.1023/B:TIME.0000016129.97430.c6}
}
Regnier, P., Lima, G., Massa, E., Levin, G. and Brandt, S. RUN: Optimal Multiprocessor Real--Time Scheduling via Reduction to Uniprocessor 2011 Proceedings of the 32nd IEEE Real--Time Systems Symposium (RTSS), pp. 104-115  inproceedings DOI URL 
Abstract: Optimal multiprocessor real--time schedulers incur significant overhead for preemptions and migrations. We present RUN, an efficient scheduler that reduces the multiprocessor problem to a series of uniprocessor problems. RUN significantly outperforms existing optimal algorithms with an upper bound of O(log m) average preemptions per job on m processors (≤ than 3 per job in all of our simulated task sets) and reduces to Partitioned EDF whenever a proper partitioning is found.
BibTeX:
@inproceedings{Regnier2011,
  author = {Regnier, Paul and Lima, George and Massa, Ernesto and Levin, Greg and Brandt, Scott},
  title = {RUN: Optimal Multiprocessor Real--Time Scheduling via Reduction to Uniprocessor},
  booktitle = {Proceedings of the 32nd IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2011},
  pages = {104--115},
  url = {papers/Regnier2011.pdf},
  doi = {http://doi.org/10.1109/RTSS.2011.17}
}
Reisinger, J., Steininger, A. and Leber, G.H. The PDCS Implementation of MARS Hardware and Software 1995 Predictably Dependable Computing Systems, pp. 209-224  incollection  
BibTeX:
@incollection{Reisinger1995,
  author = {Reisinger, Johannes and Steininger, Andreas and Leber, Günther H.},
  title = {The PDCS Implementation of MARS Hardware and Software},
  booktitle = {Predictably Dependable Computing Systems},
  publisher = {Springer--Verlag New York, Inc.},
  year = {1995},
  pages = {209--224}
}
Ripoll, I., Crespo, A. and García-Fornes, A. An Optimal Algorithm for Scheduling Soft Aperiodic Tasks in Dynamic--Priority Preemptive Systems 1997 IEEE Transactions on Software Engineering
Vol. 23(6), pp. 188-400 
article DOI URL 
Abstract: This paper addresses the problem of jointly scheduling tasks with both hard and soft real--time constraints. We present a new analysis applicable to systems scheduled using a priority preemptive dispatcher, with priorities assigned dynamically according to the EDF policy. Further, we present a new efficient on-line algorithm (the acceptor algorithm) for servicing aperiodic work load. The acceptor transforms a soft aperiodic task into a hard one by assigning a deadline. Once transformed, aperiodic tasks are handled in exactly the same way as periodic tasks with hard deadlines. The proposed algorithm is shown to be optimal in terms of providing the shortest aperiodic response time among fixed- and dynamic-priority schedulers. It always guarantees the proper execution of periodic hard tasks. The approach is composed of two parts: an off-line analysis and a run-time scheduler. The off-line algorithm runs in pseudopolynomial time O(mn), where n is the number of hard periodic tasks and m is the hyperperiod/min deadline.
BibTeX:
@article{Ripoll1997,
  author = {Ripoll, Ismael and Crespo, Alfons and García--Fornes, Ana},
  title = {An Optimal Algorithm for Scheduling Soft Aperiodic Tasks in Dynamic--Priority Preemptive Systems},
  journal = {IEEE Transactions on Software Engineering},
  year = {1997},
  volume = {23},
  number = {6},
  pages = {188--400},
  url = {papers/Ripoll1997.pdf},
  doi = {http://doi.org/10.1109/32.601081}
}
Robert, T., Fabre, J.-C. and Roy, M. On--line Monitoring of Real Time Applications for Early Error Detection 2008 Proceedings of the 14th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC), pp. 24-31  inproceedings DOI URL 
Abstract: Error confinement technologies have proven their efficiency to improve software dependability. Such mechanisms usually require efficient error detectors to swiftly signal any misbehaviour. Real--time systems, due to their timing constraints, require a richer description of correct and/or erroneous states that includes timing aspects. This paper presents real-time error detectors that can be automatically generated from formal models of the expected behaviours of software applications. The considered specifications provide the means to define quantitative temporal constraints on the execution of the application. These detectors check at run-time that the current execution matches its specification. The paper contribution is twofold. Firstly, at the theoretical level, we provide a formal definition of the expected behaviour of such detectors, ensuring a predictable behaviour of the detector system. Secondly, at a practical level, we provide a description of the complete generation process, from the models to the code of the detector.
BibTeX:
@inproceedings{Robert2008,
  author = {Robert, Thomas and Fabre, Jean--Charles and Roy, Matthieu},
  title = {On--line Monitoring of Real Time Applications for Early Error Detection},
  booktitle = {Proceedings of the 14th IEEE Pacific Rim International Symposium on Dependable Computing (PRDC)},
  publisher = {IEEE Computer Society},
  year = {2008},
  pages = {24--31},
  url = {papers/Robert2008.pdf},
  doi = {http://doi.org/10.1109/PRDC.2008.31}
}
Robert, T., Roy, M. and Fabre, J.-C. Early Error Detection for Fault Tolerance Strategies 2010 Proceedings of the 18th Real--Time and Network Systems (RTNS)  inproceedings URL 
Abstract: In this paper we present an integration of early run--time monitors in real-time systems to improve their fault tolerance properties. Early Error Detection is a mechanism that provides a theoretically optimal run-time error detection service, based on a formal specification of an application, e.g., given by a timed automata. We show how our approach can improve classical fault tolerance strategies by investigating two use-cases, namely for a design pattern that provides several degraded modes of operation, and in on-board avionics safety critical systems.
BibTeX:
@inproceedings{Robert2010,
  author = {Robert, Thomas and Roy, Matthieu and Fabre, Jean--Charles},
  title = {Early Error Detection for Fault Tolerance Strategies},
  booktitle = {Proceedings of the 18th Real--Time and Network Systems (RTNS)},
  publisher = {IRIT Press},
  year = {2010},
  url = {papers/Robert2010.pdf}
}
Rothvoß, T. On the Computational Complexity of Periodic Scheduling 2009 School: École Polytechnique Fédérale de Lausanne  phdthesis URL 
BibTeX:
@phdthesis{Rothvoss2009,
  author = {Rothvoß, Thomas},
  title = {On the Computational Complexity of Periodic Scheduling},
  school = {École Polytechnique Fédérale de Lausanne},
  year = {2009},
  url = {papers/Rothvoss2009.pdf}
}
Rushby, J.M. Design and Verification of Secure Systems 1981 Proceedings of the 8th ACM Symposium on Operating Systems Principles, pp. 12-21  inproceedings DOI URL 
Abstract: This paper reviews some of the difficulties that arise in the verification of kernelized secure systems and suggests new techniques for their resolution. It is proposed that secure systems should be conceived as distributed systems in which security is achieved partly through the physical separation of its individual components and partly through the mediation of trusted functions performed within some of those components. The purpose of a security kernel is simply to allow such a 'distributed' system to actually run within a single processor; policy enforcement is not the concern of a security kernel. This approach decouples verification of components which perform trusted functions from verification of the security kernel. This latter task may be accomplished by a new verification technique called 'proof of separability' which explicitly addresses the security relevant aspects of interrupt handling and other issues ignored by present methods.
BibTeX:
@inproceedings{Rushby1981,
  author = {Rushby, John M.},
  title = {Design and Verification of Secure Systems},
  booktitle = {Proceedings of the 8th ACM Symposium on Operating Systems Principles},
  publisher = {ACM},
  year = {1981},
  pages = {12--21},
  url = {http://doi.acm.org/10.1145/800216.806586},
  doi = {http://doi.org/10.1145/800216.806586}
}
Saha, S., Lu, Y. and Deogun, J.S. Thermal--Constrained Energy-Aware Partitioning for Heterogeneous Multi-core Multiprocessor Real-Time Systems 2012 Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 41-50  inproceedings DOI URL 
Abstract: Next--generation multi-core multiprocessor real-time systems consume less energy at the cost of increased power density. This increase in power-density results in high heat density and may affect the reliability and performance of real-time systems. Thus, incorporating maximum temperature constraints in scheduling of real-time task sets is an important challenge. This paper investigates thermal-constrained energy-aware partitioning of periodic real-time tasks in heterogeneous multi-core multiprocessor systems. We adopt a power model which considers the impact of temperature and voltage on a processor's static power consumption. Two types of thermal models are used to respectively capture negligible and non-negligible amount of heat transfer among cores. We develop a novel genetic-algorithm based approach to solve the heterogeneous multi-core multiprocessor partitioning problem. Extensive simulations were performed to validate the effectiveness of the approach. Experimental results show that integrating a worst-fit based partitioning heuristic with the genetic algorithm can significantly reduce the total energy consumption of a heterogeneous multi-core multiprocessor real-time system.
BibTeX:
@inproceedings{Saha2012,
  author = {Saha, Shivashis and Lu, Ying and Deogun, Jitender S.},
  title = {Thermal--Constrained Energy-Aware Partitioning for Heterogeneous Multi-core Multiprocessor Real-Time Systems},
  booktitle = {Proceedings of the 18th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {41--50},
  url = {papers/Saha2012.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2012.15}
}
Saifullah, A., Agrawal, K., Lu, C. and Gill, C. Multi--core Real-Time Scheduling for Generalized Parallel Task Models 2011 Proceedings of the 32nd IEEE Real--Time Systems Symposium (RTSS)  inproceedings DOI URL 
Abstract: Multi--core processors offer a significant performance increase over single core processors. Therefore, they have the potential to enable computation-intensive real-time applications with stringent timing constraints that cannot be met on traditional single-core processors. However, most results in traditional multiprocessor real-time scheduling are limited to sequential programming models and ignore intra-task parallelism. In this paper, we address the problem of scheduling periodic parallel tasks with implicit deadlines on multi-core processors. We first consider a synchronous task model where each task consists of segments, each segment having an arbitrary number of parallel threads that synchronize at the end of the segment. We propose a new task decomposition method that decomposes each parallel task into a set of sequential tasks.We prove that our task decomposition achieves a resource augmentation bound of 4 and 5 when the decomposed tasks are scheduled using global EDF and partitioned deadline monotonic scheduling, respectively. Finally, we extend our analysis to directed acyclic graph (DAG) task model where each node in the DAG has unit execution requirement. We show how these tasks can be converted into synchronous tasks such that the same transformation can be applied and the same augmentation bounds hold.
BibTeX:
@inproceedings{Saifullah2011,
  author = {Saifullah, Abusayeed and Agrawal, Kunal and Lu, Chenyang and Gill, Christopher},
  title = {Multi--core Real-Time Scheduling for Generalized Parallel Task Models},
  booktitle = {Proceedings of the 32nd IEEE Real--Time Systems Symposium (RTSS)},
  year = {2011},
  url = {papers/Saifullah2011.pdf},
  doi = {http://doi.org/10.1109/RTSS.2011.27}
}
Saifullah, A., Sankar, S., Liu, J., Lu, C., Chandra, R. and Priyantha, B. CapNet: A Real--Time Wireless Management Network for Data Center Power Capping 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 334-345  inproceedings DOI URL 
Abstract: Data center management (DCM) is increasingly becoming a significant challenge for enterprises hosting large scale online and cloud services. Machines need to be monitored, and the scale of operations mandates an automated management with high reliability and real--time performance. Existing wired networking solutions for DCM come with high cost. In this paper, we propose a wireless sensor network as a cost-effective networking solution for DCM while satisfying the reliability and latency performance requirements of DCM. We have developed CapNet, a real-time wireless sensor network for power capping, a time-critical DCM function for power management in a cluster of servers. CapNet employs an efficient event-driven protocol that triggers data collection only upon the detection of a potential power capping event. We deploy and evaluate CapNet in a data center. Using server power traces, our experimental results on a cluster of 480 servers inside the data center show that CapNet can meet the real-time requirements of power capping. CapNet demonstrates the feasibility and efficacy of wireless sensor networks for time-critical DCM applications.
BibTeX:
@inproceedings{Saifullah2014,
  author = {Saifullah, Abusayeed and Sankar, Sriram and Liu, Jie and Lu, Chenyang and Chandra, Ranveer and Priyantha, Bodhi},
  title = {CapNet: A Real--Time Wireless Management Network for Data Center Power Capping},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {334--345},
  url = {papers/Saifullah2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.35}
}
Salmani, V., Naghibzadeh, M., Taherinia, A., Bahekmat, M. and Khajouie Nejad, S. Efficiency Assessment of Job--level dynamic Scheduling Algorithms on Identical Multiprocessors 2006 Proceedings of the 10th World Scientific and Engineering Academy and Society (WSEAS), pp. 8pp.  inproceedings URL 
Abstract: This paper presents a comprehensive comparison between job--level dynamic scheduling algorithms on real-time multiprocessor environments using simulation. Earliest Deadline First (EDF) and Least Laxity First (LLF) are two well-known and extensively applied dynamic scheduling algorithms which have been proved to be optimal on uniprocessor systems. However, neither is shown to be optimal on multiprocessors. Many researches have already been done on aforementioned algorithms, but to the best of our knowledge, none of which has compared the efficiency of the two algorithms under similar conditions. Perhaps the main reason is that LLF algorithm is fully dynamic and impractical to implement. In this research, we have used a practical version of LLF which is called the Modified Least Laxity First (MLLF) algorithm instead of the traditional LLF and have compared its performance with the EDF algorithm. The MLLF is a job-level dynamic and optimal strategy on uniprocessor systems, similar to the EDF algorithm. We have investigated the performance of EDF and MLLF based on load factor from many different aspects.
BibTeX:
@inproceedings{Salmani2006,
  author = {Salmani, Vahid and Naghibzadeh, Mahmoud and Taherinia, Amirhossein and Bahekmat, Malihe and Khajouie Nejad, Sedigheh},
  title = {Efficiency Assessment of Job--level dynamic Scheduling Algorithms on Identical Multiprocessors},
  booktitle = {Proceedings of the 10th World Scientific and Engineering Academy and Society (WSEAS)},
  year = {2006},
  pages = {8pp.},
  url = {papers/Salmani2006.pdf}
}
Santinelli, L. and Cucu-Grosjean, L. A Probabilistic Calculus for Probabilistic Real-Time Systems 2015 ACM Transactions on Embedded Computing Systems
Vol. 14(3) 
article DOI URL 
Abstract: Challenges within real-time research are mostly in terms of modeling and analyzing the complexity of actual real-time embedded systems. Probabilities are effective in both modeling and analyzing embedded systems by increasing the amount of information for the description of elements composing the system. Elements are tasks and applications that need resources, schedulers that execute tasks, and resource provisioning that satisfies the resource demand. In this work, we present a model that considers component-based real-time systems with component interfaces able to abstract both the functional and nonfunctional requirements of components and the system. Our model faces probabilities and probabilistic real-time systems unifying in the same framework probabilistic scheduling techniques and compositional guarantees varying from soft to hard real time. We provide an algebra to work with the probabilistic notation developed and form an analysis in terms of sufficient probabilistic schedulability conditions for task systems with either preemptive fixed-priority or earliest deadline first scheduling paradigms.
BibTeX:
@article{Santinelli2015,
  author = {Santinelli, Luca and Cucu-Grosjean, Liliana},
  title = {A Probabilistic Calculus for Probabilistic Real-Time Systems},
  journal = {ACM Transactions on Embedded Computing Systems},
  year = {2015},
  volume = {14},
  number = {3},
  url = {papers/Santinelli2015.pdf},
  doi = {0.1145/2717113}
}
Sanvido, M.A.A., Ghosal, A. and Henzinger, T.A. xGiotto Language Report 2003 (UCB/CSD-3-1261)School: University of California Berkeley  techreport URL 
BibTeX:
@techreport{Sanvido2003,
  author = {Sanvido, Marco A. A. and Ghosal, Arkadeb and Henzinger, Thomas A.},
  title = {xGiotto Language Report},
  school = {University of California Berkeley},
  year = {2003},
  number = {UCB/CSD--3-1261},
  url = {papers/Sanvido2003.pdf}
}
Schabarg, J.-L., Boyer, M. and Fraboul, C. CAN--Ethernet architectures for real-time applications 2005 Proceedings of the 10th Conference on Emerging Technologies and Factory Automation (ETFA), pp. 252-260  inproceedings DOI URL 
Abstract: Embedded systems have specific real--time requirements that led to the development of dedicated communication protocols. Such systems must face increasing communication needs and the evolution of switched Ethernet architecture. But moving from existing dedicated field-busses architectures to new Ethernet based architectures is not always feasible, due to industrial constraints. In this paper, we compare different solutions for integrating existing data busses (such as CAN, which is an important standard in automotive context) on a global architecture that respects increasing bandwidth requirements. In a first step, we study classical CAN/CAN bridging strategies. In a second step, we propose CAN/Ethernet bridging strategies that respect the real time behavior of CAN End System when communicating through an Ethernet network that can be shared by (non CAN) applications.
BibTeX:
@inproceedings{Schabarg2005,
  author = {Schabarg, Jean--Luc and Boyer, Marc and Fraboul, Christian},
  title = {CAN--Ethernet architectures for real-time applications},
  booktitle = {Proceedings of the 10th Conference on Emerging Technologies and Factory Automation (ETFA)},
  publisher = {IEEE Computer Society},
  year = {2005},
  pages = {252--260},
  url = {papers/Schabarg2005.pdf},
  doi = {http://doi.org/10.1109/ETFA.2005.1612687}
}
Sciandra, V., Courbin, P. and George, L. Application of Mixed--Criticality Scheduling Model to Intelligent Transportation Systems Architectures 2012
Vol. 10(2)ACM SIGBED Review -- Special Issue on the Work-in-Progress (WiP) session of the 33rd IEEE Real-Time Systems Symposium (RTSS), pp. 22 
inproceedings DOI URL 
Abstract: Intelligent Transportation Systems (ITS) usage has transformed public transports' vision on operation management. However, the lack of common communication interfaces has brought redundancy within on--board applications. In this context, the European Bus System of the Future (EBSF) project has specified a common architecture based on IP standards [1]. It provides a Service Oriented Architecture (SOA) that permits the ITS applications to publish services and subscribe to others. The EBSF architecture enables Vehicle To Infrastructure communications (V2I) through a unique communication gateway, with managing needs of the different data flows depending on their priority in the network and the available communication resources (bandwidth).
BibTeX:
@inproceedings{Sciandra2012,
  author = {Sciandra, Vincent and Courbin, Pierre and George, Laurent},
  title = {Application of Mixed--Criticality Scheduling Model to Intelligent Transportation Systems Architectures},
  booktitle = {ACM SIGBED Review -- Special Issue on the Work-in-Progress (WiP) session of the 33rd IEEE Real-Time Systems Symposium (RTSS)},
  publisher = {ACM Press},
  year = {2012},
  volume = {10},
  number = {2},
  pages = {22},
  url = {papers/Sciandra2012.pdf},
  doi = {http://doi.org/10.1145/2518148.2518160}
}
Sha, L., Rajkumar, R."R. and Lehoczky, J.P. Priority Inheritance Protocols: An Approach to Real--Time Synchronization 1990 IEEE Transactions on Computers
Vol. 39(9), pp. 1175-1185 
article DOI URL 
Abstract: A direct application of commonly used synchronization primitives such as semaphores, monitors, or the Ada rendezvous can lead to uncontrolled priority inversion, a situation in which a higher priority job is blocked by lower priority jobs for an indefinite period of time. In this paper, we investigate two protocols belonging to the class of priority inheritance protocols, called the basic priority inheritance protocol and the priority ceiling protocol. We show that both protocols solve this uncontrolled priority inversion problem. In particular, the priority ceiling protocol reduces the worst case task blocking time to at most the duration of execution of a single critical section of a lower priority task. In addition, this protocol prevents the formation of deadlocks. We also derive a set of sufficient conditions under which a set of periodic tasks using this protocol is schedulable.
BibTeX:
@article{Sha1990,
  author = {Sha, Lui and Rajkumar, Ragunathan "Raj" and Lehoczky, John P.},
  title = {Priority Inheritance Protocols: An Approach to Real--Time Synchronization},
  journal = {IEEE Transactions on Computers},
  year = {1990},
  volume = {39},
  number = {9},
  pages = {1175--1185},
  url = {papers/Sha1990.pdf},
  doi = {http://doi.org/10.1109/12.57058}
}
Sha, L., Rajkumar, R."R. and Lehoczky, J.P. Priority Inheritance Protocols: An Approach to Real--Time Synchronization 1987 (CMU-CS-87-18)School: Carnegie Mellon University, Department of Computer Science  techreport  
BibTeX:
@techreport{Sha1987,
  author = {Sha, Lui and Rajkumar, Ragunathan "Raj" and Lehoczky, John P.},
  title = {Priority Inheritance Protocols: An Approach to Real--Time Synchronization},
  school = {Carnegie Mellon University, Department of Computer Science},
  year = {1987},
  number = {CMU--CS-87-18}
}
Shah, H., Coombes, A., Raabe, A., Huang, K. and Knoll, A. Measurement based WCET Analysis for Multi--core Architectures 2014 Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS), pp. 257-266  inproceedings DOI URL 
Abstract: The interference on shared resources caused by concurrently executing applications unpredictably prolongs their execution. Hence, determination of the Worst Case Execution Time (Wcet) of applications executing on shared memory multi--core processors is hard to estimate. This hinders the adoption of Commercial Off The Shelf (Cots) multi-core processors in hard real-time systems. The existing techniques opt for tailored multi-core architectures to provide high computation power at predictable execution time. However, this approach yields poor resource utilization and high costs. In this paper, we present a technique to measure the Wcet of applications on multi-core architectures using existing measurement based timing analysis tools. Our technique has a minor area impact (≈ 5%). However, this impact is limited to the emulation devices only and production chips remain unchanged. Thus, our technique does not impact performance of the Cots chips by any ways. The technique is demonstrated by measuring Wcet of benchmark applications using the RapiTime timing analysis tool. The tests are conducted on a quad-core NIOS II processor on an Altera Fpga.
BibTeX:
@inproceedings{Shah2014,
  author = {Shah, Hardik and Coombes, Andrew and Raabe, Andreas and Huang, Kay and Knoll, Alois},
  title = {Measurement based WCET Analysis for Multi--core Architectures},
  booktitle = {Proceeding of the 22nd International Conference on Real--Time and Network Systems (RTNS)},
  publisher = {ACM Press},
  year = {2014},
  pages = {257--266},
  url = {papers/Shah2014.pdf},
  doi = {http://doi.org/10.1145/2659787.2659819}
}
Shin, I., Easwaran, A. and Lee, I. Hierarchical Scheduling Framework for Virtual Clustering of Multiprocessors 2008 Proceedings of the 20th Euromicro Conference on Real-Time Systems (ECRTS), pp. 181-190  inproceedings DOI URL 
Abstract: Scheduling of sporadic task systems on multiprocessor platforms is an area which has received much attention in the recent past. It is widely believed that finding an optimal scheduler is hard, and therefore most studies have focused on developing algorithms with good utilization bounds. These algorithms can be broadly classified into two categories: partitioned scheduling in which tasks are statically assigned to individual processors, and globalscheduling in which each task is allowed to execute on any processor in the platform. In this paper we consider a third, more general, approach called cluster-based scheduling. In this approach each task is statically assigned to a processor cluster, tasks in each cluster areglobally scheduled among themselves, and clusters in turn are scheduled on the multiprocessor platform. We develop techniques to support such cluster-based scheduling algorithms, and also consider properties that minimize processor utilization of individual clusters. Since neither partitioned nor global strategies dominate over the other, cluster-based scheduling is a natural direction for research towards achieving improved utilization bounds.
BibTeX:
@inproceedings{Shin2008,
  author = {Shin, Insik and Easwaran, Arvind and Lee, Insup},
  title = {Hierarchical Scheduling Framework for Virtual Clustering of Multiprocessors},
  booktitle = {Proceedings of the 20th Euromicro Conference on Real-Time Systems (ECRTS)},
  year = {2008},
  pages = {181--190},
  url = {/papers/Shin2008.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2008.28}
}
Shin, I. and Lee, I. Compositional real-time scheduling framework 2004 Proceedings of the 25th IEEE Real-Time Systems Symposium (RTSS), pp. 57-67  inproceedings DOI URL 
Abstract: Our goal is to develop a compositional real-time scheduling framework so that global (system-level) timing properties can be established by composing independently (specified and) analyzed local (component-level) timing properties. The two essential problems in developing such a framework are: (1) to abstract the collective real-time requirements of a component as a single real-time requirement and (2) to compose the component demand abstraction results into the system-level real-time requirement. In our earlier work, we addressed the problems using the Liu and Layland periodic model. In this paper, we address the problems using another well-known model, a bounded-delay resource partition model, as a solution model to the problems. To extend our framework to this model, we develop an exact feasibility condition for a set of bounded-delay tasks over a bounded-delay resource partition. In addition, we present simulation results to evaluate the overheads that the component demand abstraction results incur in terms of utilization increase. We also present utilization bound results on a bounded-delay resource model.
BibTeX:
@inproceedings{Shin2004,
  author = {Shin, Insik and Lee, Insup},
  title = {Compositional real-time scheduling framework},
  booktitle = {Proceedings of the 25th IEEE Real-Time Systems Symposium (RTSS)},
  year = {2004},
  pages = {57--67},
  url = {/papers/Shin2004.pdf},
  doi = {http://doi.org/10.1109/REAL.2004.15}
}
Shin, I. and Lee, I. Periodic resource model for compositional real-time guarantees 2003 Proceedings of the 24th IEEE Real-Time Systems Symposium (RTSS), pp. 2-13  inproceedings DOI URL 
Abstract: We address the problem of providing compositional hard real-time guarantees in a hierarchy of schedulers. We first propose a resource model to characterize a periodic resource allocation and present exact schedulability conditions for our proposed resource model under the EDF and RM algorithms. Using the exact schedulability conditions, we then provide methods to abstract the timing requirements that a set of periodic tasks demands under the EDF and RM algorithms as a single periodic task. With these abstraction methods, for a hierarchy of schedulers, we introduce a composition method that derives the timing requirements of a parent scheduler from the timing requirements of its child schedulers in a compositional manner such that the timing requirement of the parent scheduler is satisfied, if and only if the timing requirements of its child schedulers are satisfied.
BibTeX:
@inproceedings{Shin2003,
  author = {Shin, Insik and Lee, Insup},
  title = {Periodic resource model for compositional real-time guarantees},
  booktitle = {Proceedings of the 24th IEEE Real-Time Systems Symposium (RTSS)},
  year = {2003},
  pages = {2--13},
  url = {/papers/Shin2003.pdf},
  doi = {http://doi.org/10.1109/REAL.2003.1253249}
}
Siebert, F. JEOPARD – Java Environment for Parallel Real--Time Development 2009 Proceedings of 12th International Symposium on Object/Component/Service--Oriented Real-Time Distributed Computing (ISORC), pp. 28-36  inproceedings DOI URL 
Abstract: Multicore systems have become standard for desktop computers today. Current operating systems and software development tools provide straightforward means to use the additional computing power. However, a more fundamental change in the design and development of software is required to fully exploit the power of multicore systems. Furthermore, the fast growing market of embedded systems is currently largely unaffected by the introduction of multicore systems. This will change quickly in the future, which will mean that there will be a demand on efficient development of reliable embedded software that can give real--time guarantees and exploit the available power on multicore systems. The JEOPARD project addresses this demand by developing Java software tools to exploit multicore power while ensuring correctness and predictable timing. This paper gives an overview of the JEOPARD project and focuses on key technical issues such as real-time scheduling and realtime garbage collection on multi-core systems.
BibTeX:
@inproceedings{Siebert2009,
  author = {Siebert, Fridtjof},
  title = {JEOPARD – Java Environment for Parallel Real--Time Development},
  booktitle = {Proceedings of 12th International Symposium on Object/Component/Service--Oriented Real-Time Distributed Computing (ISORC)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {28--36},
  url = {papers/Siebert2009.pdf},
  doi = {http://doi.org/10.1109/ISORC.2009.48}
}
Siebert, F. Limits of parallel marking garbage collection 2008 Proceedings of the 7th international Symposium on Memory Management (ISMM), pp. 21-29  inproceedings DOI URL 
Abstract: More and more, parallel multicore systems will be used even in low--end devices such as embedded controllers that require realtime guarantees. When garbage collection is used in these systems, parallel or concurrent garbage collection brings important performance advantages. In the context of realtime systems, it has to be shown that a parallel garbage collector implementation not only performs well in most cases, but guarantees on its performance in the worst case are required. This paper analyses the difficulties a parallel mark-and-sweep garbage collector faces during a parallel mark phase. The performance of such a garbage collector degrades when only some of the available processors can perform scanning work in the mark phase. Whenever the grey set contains fewer elements than the number of available processors, some processors may be stalled waiting for new objects to be added to the grey set. This paper gives an upper bound for the number of stalls that may occur as a function of simple properties of the memory graph. This upper bound is then determined for the Java applications that are part of the SPECjvm98 benchmark suite and the theoretical worst-case scalability of a parallel mark phase is analysed. The presented approach is then applied to a Java virtual machine that has uniform mark steps, which at first results in poor worst-case scalability. A small change in the implementation is then proposed and analysed to achieve good scalability even in the worst case.
BibTeX:
@inproceedings{Siebert2008,
  author = {Siebert, Fridtjof},
  title = {Limits of parallel marking garbage collection},
  booktitle = {Proceedings of the 7th international Symposium on Memory Management (ISMM)},
  publisher = {ACM},
  year = {2008},
  pages = {21--29},
  url = {papers/Siebert2008.pdf},
  doi = {http://doi.org/10.1145/1375634.1375638}
}
Sikora, F. Aspects algorithmiques de la comparaison d'éléments biologiques 2011 School: Université Paris--Est Marne-la-Vallée  phdthesis URL 
Abstract: To investigate the complex links between genotype and phenotype, one can study the relations between different biological entities. It forms a biological network, represented by a graph. In this thesis, we are interested in the occurrence of a motif (a multi--set of colors) in a vertex-colored graph, representing a biological network. Such motifs usually correspond to a set of elements realizing a same function, and which may have been evolutionarily preserved. We follow the algorithmic study of this problem, by establishing hard instances and studying possibilities to cope with the hardness (parameterized complexity, preprocessing, approximation...). We also develop a plugin for Cytoscape, in order to solve efficiently this problem and to test it on real data.We are also interested in different problems related to comparative genomics. The scientific method is the same: studying problems arising from biology, specifying the hard instances and giving solutions to cope with the hardness (or proving such solutions are unlikely).
BibTeX:
@phdthesis{Sikora2011,
  author = {Sikora, Florian},
  title = {Aspects algorithmiques de la comparaison d'éléments biologiques},
  school = {Université Paris--Est Marne-la-Vallée},
  year = {2011},
  url = {papers/Sikora2011.pdf}
}
Singhoff, F., Jérôme, L., Nana, L. and Marcé, L. Cheddar : a Flexible Real Time Scheduling Framework 2004 ACM SIGAda Ada Letters
Vol. 24(4), pp. 1-8 
article DOI URL 
Abstract: This paper describes an Ada framework called Cheddar which provides tools to check if a real time application meets its temporal constraints. The framework is based on the real time scheduling theory and is mostly written for educational purposes. With Cheddar, an application is defined by a set of processors, tasks, buffers, shared resources and messages. Cheddar provides feasibility tests in cases of monoprocessor, multiprocessor and distributed systems. It also provides a flexible simulation engine which allows the designer to describe and run simulations of specific systems. The framework is open and has been designed to be easily connected to CASE tools such as editors, design tools, simulators, ...
BibTeX:
@article{Singhoff2004,
  author = {Singhoff, Frank and Legrand Jérôme and Nana, Laurent and Marcé, Lionel},
  title = {Cheddar : a Flexible Real Time Scheduling Framework},
  journal = {ACM SIGAda Ada Letters},
  year = {2004},
  volume = {24},
  number = {4},
  pages = {1--8},
  note = {http://beru.univ--brest.fr/ singhoff/cheddar/},
  url = {papers/Singhoff2004.pdf},
  doi = {http://doi.org/10.1145/1046191.1032298}
}
Sjödin, M. and Hansson, H. Improved Response--Time Analysis Calculations 1998 Proceedings of the 19th IEEE Real--Time Systems Symposium (RTSS), pp. 399-408  inproceedings DOI URL 
Abstract: Schedulability analysis of fixed priority preemptive scheduled systems can be performed by calculating the worst--case response-time of the involved processes. The system is deemed schedulable if the calculated responsetime for each process is less than its corresponding deadline. It is desirable that the Response-Time Analysis (RTA) can be efficiently performed. This is particularly important in dynamic real-time systems when a fast response is needed to decide whether a new job can be accommodated, or when the RTA is extensively applied, e.g., when used to guide the heuristics in a higher level optimiser. This paper presents a set of methods to improve the efficiency of RTA calculations. The methods are proved correct, in the sense that they give the same results as traditional (non-improved) RTA. We also present an evaluation of the improvements, by applying them to the particularly time-consuming traffic model used in RTA for ATM communication networks. Our evaluation shows that the proposed methods can give an order of magnitude reduction of the execution time of RTA.
BibTeX:
@inproceedings{Sjoedin1998,
  author = {Sjödin, Mikael and Hansson, Hans},
  title = {Improved Response--Time Analysis Calculations},
  booktitle = {Proceedings of the 19th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1998},
  pages = {399--408},
  url = {papers/Sjoedin1998.pdf},
  doi = {http://doi.org/10.1109/REAL.1998.739773}
}
Spliet, R., Vanga, M., Brandenburg, B.B. and Dziadek, S. Fast on Average, Predictable in the Worst Case: Exploring Real--Time Futexes in LITMUSRT 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 96-105  inproceedings DOI URL 
Abstract: This paper explores the problem of how to improve the average--case performance of real-time locking protocols, preferably without significantly deteriorating worst-case performance. Motivated by the futex implementation in Linux, where uncontended lock operations under the Priority Inheritance Protocol (PIP) do not incur mode-switching overheads, we extend this concept to more sophisticated protocols; namely the PCP, the MPCP and the FMLP + . We identify the challenges involved in implementing futexes for these protocols and present the design and evaluation of their implementations in LITMUS RT, a real-time extension of the Linux kernel. Our evaluation shows substantial improvements in the uncontended case (e.g., a futex implementation of the PCP lowers lock acquisition and release overheads by up to 75% and 92%, respectively), at the expense of some increases in worst-case overhead on par with Linux’s existing futex implementation.
BibTeX:
@inproceedings{Spliet2014,
  author = {Spliet, Roy and Vanga, Manohar and Brandenburg, Björn B. and Dziadek, Sven},
  title = {Fast on Average, Predictable in the Worst Case: Exploring Real--Time Futexes in LITMUSRT},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {96--105},
  url = {papers/Spliet2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.33}
}
Spuri, M. Analysis of Deadline Scheduled Real--Time 1996 (2772)School: Institut national de recherche en informatique et en automatique (INRIA)  techreport URL 
Abstract: A uniform, flexible approach is proposed for analysing the feasibility of deadline scheduled real--time systems. In its most general formulation, the analysis assumes sporadically periodic tasks with arbitrary deadlines, release jitter, and shared resources. System overheads of a tick driven scheduler implementation, and scheduling of soft aperiodic tasks are also accounted for. A procedure for the computation of task worst-case response times is also described for the same model. While this problem has been largely studied in the context of fixed priority systems, we are not aware of other works that have proposed a solution to it when deadline scheduling is assumed. The worst-case response time evaluation is a fundamental tool for analysing end-to-end timing constraints in distributed systems Ti94b.
BibTeX:
@techreport{Spuri1996,
  author = {Spuri, Marco},
  title = {Analysis of Deadline Scheduled Real--Time},
  school = {Institut national de recherche en informatique et en automatique (INRIA)},
  year = {1996},
  number = {2772},
  url = {papers/Spuri1996.pdf}
}
Spuri, M. Holistic Analysis for Deadline Scheduled Real--Time Distributed Systems 1996 (RR-2873)School: INRIA  techreport URL 
Abstract: The holistic theory is a very interesting approach formerly proposed by Tindell and Clark Tin94b for assessing the feasibility of fixed priority real--time systems. Its major merit is to make the analysis of distributed systems tractable, without being at the same time too pessimistic. In this paper we extend the holistic theory to the analysis of deadline scheduled real-time distributed systems. Owing to its predictability, the Timed Token MAC protocol is assumed to arbitrate network accesses among host processors. Furthermore, in order to achieve a large resource utilization, outgoing packets are assumed to be locally queued earliest deadline first. A procedure for the computation of worst-case message communication delays is also given. The theory described in the paper is validated by means of a case study application, in which worst-case response times of end-to-end computations are tightly bounded. The example has confirmed the effectiveness of a global deadline scheduling approach.
BibTeX:
@techreport{Spuri1996b,
  author = {Spuri, Marco},
  title = {Holistic Analysis for Deadline Scheduled Real--Time Distributed Systems},
  school = {INRIA},
  year = {1996},
  number = {RR--2873},
  url = {papers/Spuri1996b.pdf}
}
Spuri, M. and Buttazzo, G.C. Scheduling Aperiodic Tasks in Dynamic Priority Systems 1996 Real--Time Systems
Vol. 10(2), pp. 179-210 
article DOI URL 
Abstract: In this paper we present five new on--line algorithms for servicing soft aperiodic requests in realtime systems, where a set of hard periodic tasks is scheduled using the Earliest Deadline First (EDF) algorithm. All the proposed solutions can achieve full processor utilization and enhance aperiodic responsiveness, still guaranteeing the execution of the periodic tasks. Operation of the algorithms, performance, schedulability analysis, and implementation complexity are discussed and compared with classical alternative solutions, such as background and polling service. Extensive simulations show that algorithms with contained run-time overhead present nearly optimal responsiveness. A valuable contribution of this work is to provide the real-time system designer with a wide range of practical solutions which allow to balance efficiency against implementation complexity.
BibTeX:
@article{Spuri1996a,
  author = {Spuri, Marco and Buttazzo, Giorgio C.},
  title = {Scheduling Aperiodic Tasks in Dynamic Priority Systems},
  journal = {Real--Time Systems},
  year = {1996},
  volume = {10},
  number = {2},
  pages = {179--210},
  url = {papers/Spuri1996a.pdf},
  doi = {http://doi.org/10.1007/BF00360340}
}
Spuri, M. and Buttazzo, G.C. Efficient Aperiodic Service under Earliest Deadline Scheduling 1994 Proceedings of the 15th IEEE Real--Time Systems Symposium (RTSS), pp. 2-11  inproceedings DOI URL 
Abstract: We present four new on--line algorithms for servicing soft aperiodic requests in real-time systems, where a set of hard periodic tasks is scheduled using the Earliest Deadline First (EDF) algorithm. All the proposed solutions can achieve full processor utilization and enhance aperiodic responsiveness, still guaranteeing the execution of the periodic tasks. Operation of the algorithms, performance, schedulability analysis, and implementation complexity are discussed and compared with classical alternative solutions, such as background and polling service. Extensive simulations show that algorithms with contained run-time overhead present nearly optimal responsiveness. A valuable contribution of this work is to provide the real-time system designer with a wide range of practical solutions which allow to balance efficiency against implementation complexity.
BibTeX:
@inproceedings{Spuri1994,
  author = {Spuri, Marco and Buttazzo, Giorgio C.},
  title = {Efficient Aperiodic Service under Earliest Deadline Scheduling},
  booktitle = {Proceedings of the 15th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1994},
  pages = {2--11},
  url = {papers/Spuri1994.pdf},
  doi = {http://doi.org/10.1109/REAL.1994.342735}
}
Srinivasan, A. and Anderson, J.H. Optimal rate--based scheduling on multiprocessors 2002 Proceedings of the 34th Annual ACM Symposium on Theory of Computing (STOC), pp. 189-198  inproceedings DOI URL 
Abstract: The PD2 Pfair/ERfair scheduling algorithm is the most efficient known algorithm for optimally scheduling periodic tasks on multiprocessors. In this paper, we prove that PD2 is also optimal for scheduling "rate--based" tasks whose processing steps may be highly jittered. The rate-based task model we consider generalizes the widely-studied sporadic task model.
BibTeX:
@inproceedings{Srinivasan2002a,
  author = {Srinivasan, Anand and Anderson, James H.},
  title = {Optimal rate--based scheduling on multiprocessors},
  booktitle = {Proceedings of the 34th Annual ACM Symposium on Theory of Computing (STOC)},
  publisher = {ACM},
  year = {2002},
  pages = {189--198},
  url = {papers/Srinivasan2002a.pdf},
  doi = {http://doi.org/10.1145/509907.509938}
}
Srinivasan, A. and Baruah, S.K. Deadline--based scheduling of periodic task systems on multiprocessors 2002 Information Processing Letters
Vol. 84(2) 
article DOI URL 
Abstract: We consider the problem of scheduling periodic task systems on multiprocessors and present a deadline--based scheduling algorithm for solving this problem. We show that our algorithm successfully schedules on m processors any periodic task system with utilization at most m2/(2m−1).
BibTeX:
@article{Srinivasan2002,
  author = {Srinivasan, Anand and Baruah, Sanjoy K.},
  title = {Deadline--based scheduling of periodic task systems on multiprocessors},
  journal = {Information Processing Letters},
  year = {2002},
  volume = {84},
  number = {2},
  url = {papers/Srinivasan2002.pdf},
  doi = {http://doi.org/10.1016/S0020--0190(02)00231-4}
}
Stankovic, J.A. Misconceptions About Real--Time Computing: A Serious Problem for Next-Generation Systems 1988 Computer
Vol. 21(10), pp. 10-19 
article DOI URL 
Abstract: The author defines real--time computing and states and dispels the most common misconceptions about it. He discusses the fundamental technical issues of real-time computing. He examines specification and verification, scheduling theory, operating systems, programming languages and design methodology, distributed databases, artificial intelligence, fault tolerance, architectures, and communication.
BibTeX:
@article{Stankovic1988,
  author = {Stankovic, John A.},
  title = {Misconceptions About Real--Time Computing: A Serious Problem for Next-Generation Systems},
  journal = {Computer},
  year = {1988},
  volume = {21},
  number = {10},
  pages = {10--19},
  url = {papers/Stankovic1988.pdf},
  doi = {http://doi.org/10.1109/2.7053}
}
Stavrou, K. and Trancoso, P. Thermal--Aware Scheduling: A solution for Future Chip Multiprocessors Thermal Problems 2006 Proceedings of the 9th Euromicro Conference Digital System Design: Architectures, Methods and Tools (DSD), pp. 123-126  inproceedings DOI URL 
Abstract: The increased complexity and operating frequency in current microprocessors is resulting in a decrease in the performance improvements. In order to keep up with the expected performance gains, major manufacturers have started to offer chip--multiprocessor architectures. Nevertheless, the integration of several cores on the same chip leads to increased heat dissipation and consequently additional costs, decrease of the reliability, and performance loss, among others. In this paper we propose thermal-aware scheduling (TAS) a technique that aims to minimize all these problems. When assigning processes to cores, TAS takes their temperature into account avoiding thermal violation events. As a side effect, the performance is improved. Simulation results show that for a 25-core CMP, a simple TAS heuristic reduces the performance loss that is introduced by excessive temperature, from 52% to 18%. At the same time, TAS decreases the chip's temperature by 2.6°C.
BibTeX:
@inproceedings{Stavrou2006,
  author = {Stavrou, Kyriakos and Trancoso, Pedro},
  title = {Thermal--Aware Scheduling: A solution for Future Chip Multiprocessors Thermal Problems},
  booktitle = {Proceedings of the 9th Euromicro Conference Digital System Design: Architectures, Methods and Tools (DSD)},
  publisher = {IEEE Computer Society},
  year = {2006},
  pages = {123--126},
  url = {papers/Stavrou2006.pdf},
  doi = {http://doi.org/10.1109/DSD.2006.88}
}
Steiger, C., Walder, H., Platzner, M. and Thiele, L. Online scheduling and placement of real--time tasks to partially reconfigurable devices 2003 Proceedings of the 24th IEEE Real--Time Systems Symposium (RTSS), pp. 224-235  inproceedings DOI URL 
Abstract: This paper deals with online scheduling of tasks to partially reconfigurable devices. Such devices are able to execute several tasks in parallel. All tasks share the reconfigurable surface as a single resource which leads to highly dynamic allocation situations. To manage such devices at runtime, we propose a reconfigurable operating system that splits into three main modules: scheduler, placer, and loader. The main characteristics of the resulting online scheduling problem is the strong nexus between scheduling and placement. We discuss a fast online placement technique and then focus on scheduling real--time tasks. We devise guarantee-based schedulers for two scenarios, namely tasks with arbitrary and synchronous arrival times. The schedulers exploit the knowledge about task properties to improve the system’s performance. The experiments show that the developed schedulers lead to substantial performance gains at an acceptable run-time overhead.
BibTeX:
@inproceedings{Steiger2003,
  author = {Steiger, Christoph and Walder, Herbert and Platzner, Marco and Thiele, Lothar},
  title = {Online scheduling and placement of real--time tasks to partially reconfigurable devices},
  booktitle = {Proceedings of the 24th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2003},
  pages = {224--235},
  url = {papers/Steiger2003.pdf},
  doi = {http://doi.org/10.1109/REAL.2003.1253269}
}
Su, L., Li, Q., Hu, S., Wang, S., Gao, J., Liu, H., Abdelzaher, T.F., Han, J., Liu, X., Gao, Y. and Kaplan, L.M. Generalized Decision Aggregation in Distributed Sensing Systems 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 1-10  inproceedings DOI URL 
Abstract: In this paper, we present GDA, a generalized decision aggregation framework that integrates information from distributed sensor nodes for decision making in a resource efficient manner. Traditional approaches that target similar problems only take as input the discrete label information from individual sensors that observe the same events. Different from them, our proposed GDA framework is able to take advantage of the confidence information of each sensor about its decision, and thus achieves higher decision accuracy. Targeting generalized problem domains, our framework can naturally handle the scenarios where different sensor nodes observe different sets of events whose numbers of possible classes may also be different. GDA also makes no assumption about the availability level of ground truth label information, while being able to take advantage of any if present. For these reasons, our approach can be applied to a much broader spectrum of sensing scenarios. The advantages of our proposed framework are demonstrated through both theoretic analysis and extensive experiments.
BibTeX:
@inproceedings{Su2014,
  author = {Su, Lu and Li, Qi and Hu, Shaohan and Wang, Shiguang and Gao, Jing and Liu, Hengchang and Abdelzaher, Tarek F. and Han, Jiawei and Liu, Xue and Gao, Yan and Kaplan, Lance M.},
  title = {Generalized Decision Aggregation in Distributed Sensing Systems},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {1--10},
  url = {papers/Su2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.40}
}
Takada, H. and Sakamura, K. A novel approach to multiprogrammed multiprocessor synchronization for real--time kernels 1997 Proceedings of the 18th IEEE Real--Time Systems Symposium (RTSS), pp. 134-143  inproceedings DOI URL 
Abstract: In order to solve the problem of inopportune preemption in multiprogrammed multiprocessor synchronization, two strategies which are applicable to real--time systems have been investigated: preemption-safe locking and wait-free synchronization. Both of them, however, have a problem for use in the implementation of a real-time kernel. Preemption-safe locking has the drawback that the preemption cost becomes large; while wait-free operations on complex data structures are generally very inefficient and are not practical. We propose a novel approach to multiprogrammed multiprocessor synchronization, called the SPEPP (Spinning Processor Executes for Preempted Processors) synchronization, with which the preemption cost can be reduced to almost zero, while operations on complex data structures can be realized with reasonable efficiency. This paper presents the two algorithms of the SPEPP synchronization and their extensions, and demonstrates its effectiveness through the performance measurements of real-time kernels implemented with the SPEPP synchronization algorithms.
BibTeX:
@inproceedings{Takada1997,
  author = {Takada, Hiroaki and Sakamura, Ken},
  title = {A novel approach to multiprogrammed multiprocessor synchronization for real--time kernels},
  booktitle = {Proceedings of the 18th IEEE Real--Time Systems Symposium (RTSS)},
  year = {1997},
  pages = {134--143},
  url = {papers/Takada1997.pdf},
  doi = {http://doi.org/10.1109/REAL.1997.641276}
}
Terraneo, F., Rinaldi, L., Maggio, M. and Papadopoulos Alessandro Vittorio, L.A. FLOPSYNC--2: Efficient Monotonic Clock Synchronisation 2014 Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS), pp. 11-20  inproceedings DOI URL 
Abstract: Time synchronisation is crucial for distributed systems, and particularly for Wireless Sensor Networks (WSNs), where each node is executing concurrent operations to achieve a real--time objective. However, synchronisation is quite difficult to achieve in WSNs, due to the unpredictable deployment conditions and to physical effects like thermal stress, that cause drifts in the local node clocks. As a result, state-of-the-art synchronisation schemes do not guarantee monotonicity of the nodes clock, or are relying on external hardware assistance. In this paper we present FLOPSYNC-2, a scheme to synchronise the clocks of multiple nodes in a WSN, requiring no additional hardware, and based on the application of control-theoretical principles. The scheme guarantees low overhead, low power consumption and synchronisation with clock monotonicity. We propose an implementation of FLOPSYNC-2 on top of the microcontroller operating system Miosix, and prove the validity of our claims with several-days-long experiments on an eight-hop network. The experimental results show that the average clock difference among nodes is limited to a hundred of ns, with a sub-μs standard deviation. By introducing a suitable power model, we also prove that synchronisation is achieved with a sub-μA consumption overhead.
BibTeX:
@inproceedings{Terraneo2014,
  author = {Terraneo, Federico and Rinaldi, Luigi and Maggio, Martina and Papadopoulos, Alessandro Vittorio, Leva, Alberto},
  title = {FLOPSYNC--2: Efficient Monotonic Clock Synchronisation},
  booktitle = {Proceedings of the 35th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {11--20},
  url = {papers/Terraneo2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.14}
}
Timesys http://www.timesys.com/java/   electronic URL 
BibTeX:
@electronic{RI,
  author = {Timesys},
  title = {http://www.timesys.com/java/},
  url = {http://www.timesys.com/java/}
}
Tindell, K.W. Adding time-offsets to schedulability analysis 1994 (YCS-94-221)School: University of York, Department of Computer Science  techreport URL 
Abstract: This paper discusses the addition of so--called time offsets to task sets dispatched according to fixed priorities. The motivation for this work is two-fold: firstly, direct expression of time offsets is a useful structuring approach for designing complex hard real-time systems. Secondly, analysis directly addressing time offsets can be very much less pessimistic than extant analysis. In this report we extend our current fixed priority schedulability analysis, and then present two major worked examples, illustrating the approach.
BibTeX:
@techreport{Tindell1994,
  author = {Tindell, Ken W.},
  title = {Adding time-offsets to schedulability analysis},
  school = {University of York, Department of Computer Science},
  year = {1994},
  number = {YCS--94-221},
  url = {papers/Tindell1994.pdf}
}
Tindell, K.W. and Burns, A. Guaranteeing message latencies on control area network (CAN) 1994 Proceedings of 1st international CAN conference, pp. 1-11  inproceedings URL 
Abstract: A generally perceived problem with CAN is that it is unable to guarantee the timing performance of lower priority messages. Recent work has developed analysis to bound message latencies under arbitrary error rate assumptions. Messages are permitted to be periodic or sporadic, with few restrictions on deadlines. The analysis can give optimal identifier orderings, and be used to ask “what if” questions. In this paper we derive the analysis and apply it to an SAE ‘benchmark’, assuming the Intel 82527 stand--alone CAN controller is used.
BibTeX:
@inproceedings{Tindell1994a,
  author = {Tindell, Ken W. and Burns, Alan},
  title = {Guaranteeing message latencies on control area network (CAN)},
  booktitle = {Proceedings of 1st international CAN conference},
  year = {1994},
  pages = {1--11},
  url = {papers/Tindell1994a.pdf}
}
Tindell, K.W., Burns, A. and Wellings, A.J. Calculating controller area network (can) message response times 1995 Control Engineering Practice
Vol. 3(8), pp. 1163-1169 
article DOI URL 
Abstract: Controller Area Network (CAN) is a well--designed communications bus for sending and receiving short real-time control messages at speeds of up to 1Mbit/sec. One of the perceived drawbacks to CAN has been the inability to bound accurately the worst-case response time of a given message (i.e., the longest time between queueing the message and the message arriving at the destination processors). This paper presents an analysis to bound such latencies. A benchmark is used to illustrate the application of this analysis.
BibTeX:
@article{Tindell1995,
  author = {Tindell, Ken W. and Burns, Alan and Wellings, Andy J.},
  title = {Calculating controller area network (can) message response times},
  journal = {Control Engineering Practice},
  year = {1995},
  volume = {3},
  number = {8},
  pages = {1163--1169},
  url = {papers/Tindell1995.pdf},
  doi = {http://doi.org/10.1016/0967--0661(95)00112-8}
}
Tindell, K.W., Burns, A. and Wellings, A.J. An Extendible Approach for Analyzing Fixed Priority Hard Real--Time Tasks 1994 Real--Time Systems
Vol. 6(2), pp. 133-152 
article URL 
Abstract: As the real--time computing industry moves away from static cyclic executive-based scheduling towards more flexible process-based scheduling, so it is important for current scheduling analysis techniques to advance and to address more realistic application areas. This paper extends the current analysis associated with static priority pre-emptive based scheduling; in particular it derives analysis for tasks with arbitrary deadlines that may suffer release jitter due to being dispatched by a tick driven scheduler. We also consider bursty sporadic activities, where tasks arrive sporadically but then execute periodically for some bounded time. The paper illustrates how a window-based analysis technique can be used to find the worst-case response time of a task set, and shows that the technique can be easily extended to cope with realistic and complex task characteristics.
BibTeX:
@article{Tindell1994b,
  author = {Tindell, Ken W. and Burns, Alan and Wellings, Andy J.},
  title = {An Extendible Approach for Analyzing Fixed Priority Hard Real--Time Tasks},
  journal = {Real--Time Systems},
  year = {1994},
  volume = {6},
  number = {2},
  pages = {133--152},
  url = {papers/Tindell1994b.pdf}
}
Tindell, K.W., Burns, A. and Wellings, A.J. Allocating Hard Real--Time tasks: An NP-Hard Problem Made Easy 1992 Real--Time Systems
Vol. 4(2), pp. 145-165 
article DOI URL 
Abstract: A distributed hard real time system can be composed from a number of communicating tasks. One of the difficulties with building such systems is the problem of where to place the tasks. In general there are P T ways of allocating T tasks to P processors, and the problem of finding an optimal feasible allocation (where all tasks meet physical and timing constraints) is known to be NP--Hard. This paper describes an approach to solving the task allocation problem using a technique known as simulated annealing. It also defines a distributed hard real-time architecture and presents new analysis which enables timing requirements to be guaranteed.
BibTeX:
@article{Tindell1992,
  author = {Tindell, Ken W. and Burns, Alan and Wellings, Andy J.},
  title = {Allocating Hard Real--Time tasks: An NP-Hard Problem Made Easy},
  journal = {Real--Time Systems},
  year = {1992},
  volume = {4},
  number = {2},
  pages = {145--165},
  url = {papers/Tindell1992.pdf},
  doi = {http://doi.org/10.1007/BF00365407}
}
Tindell, K.W. and Clark, J. Holistic schedulability analysis for distributed hard real--time systems 1994 Microprocessing and Microprogramming
Vol. 40(2), pp. 117-134 
article DOI URL 
Abstract: This paper extends the current analysis associated with static priority pre--emptive based scheduling to address the wider problem of analysing schedulability of a distributed hard real-time system; in particular it derives analysis for a distributed system where tasks with arbitrary deadlines communicate by message passing and shared data areas. A simple TDMA protocol is assumed, and analysis developed to bound not only the communications delays, but also the delays and overheads incurred when messages are processed by the protocol stack at the destination processor. The paper illustrates how a window-based analysis technique can be used to find the worst-case response times of a distributed task set. An extended example illustrating the application of the analysis is presented.
BibTeX:
@article{Tindell1994d,
  author = {Tindell, Ken W. and Clark, John},
  title = {Holistic schedulability analysis for distributed hard real--time systems},
  journal = {Microprocessing and Microprogramming},
  year = {1994},
  volume = {40},
  number = {2},
  pages = {117--134},
  url = {papers/Tindell1994d.pdf},
  doi = {http://doi.org/10.1016/0165--6074(94)90080-9}
}
Tindell, K.W., Hansson, H. and Wellings, A.J. Analysing real--time communications: controller area network (CAN) 1994 Proceedings of the 15th IEEE Real--Time Systems Symposium (RTSS), pp. 259-263  inproceedings DOI URL 
Abstract: The increasing use of communication networks in time--critical applications presents engineers with fundamental problems with the determination of response times of communicating distributed processes. Although there has been some work on the analysis of communication protocols, most of this is for idealised networks. Experience with single-processor scheduling analysis has shown that models which abstract away from implementation details are at best very pessimistic, and at worst lead to an unschedulable system being deemed schedulable. In this paper, we derive an idealised scheduling analysis for the CAN real-time bus, and then study two actual interface chips to see how the analysis can be applied.
BibTeX:
@inproceedings{Tindell1994c,
  author = {Tindell, Ken W. and Hansson, Hans and Wellings, Andy J.},
  title = {Analysing real--time communications: controller area network (CAN)},
  booktitle = {Proceedings of the 15th IEEE Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {1994},
  pages = {259--263},
  url = {papers/Tindell1994c.pdf},
  doi = {http://doi.org/10.1109/REAL.1994.342710}
}
Trabelsi, K. and Fauberteau, F. Margin--Aware Partitioning for Real-Time Multiprocessor Systems 2012 Proceedings of the 6th Junior Researcher Workshop on Real--Time Computing (JRWRTC), pp. 7-12  inproceedings URL 
Abstract: This paper focus on temporal robustness in real--time multiprocessor systems. We consider as margin on the Worst Case Execution Time (WCET) the time during which a task can continue its execution when it has run for its WCET. In order to provide a robust system, we intend to produce a task assignment among the processors such that the margin values of all the tasks are maximized function of defined coefficients. This margin can then be consumed by the task after it has been executed for its WCET, even if all the other tasks also consume their margin. We propose a linear programming model in order to solve this partitioning problem. Two approaches are defined in this paper : the LP-MaxMargin model and its extension LP-FairMargin. The LP-MaxMargin model pushes the solver to give maximum margin to the tasks with the highest coefficient at the expense of tasks with lower coefficients. Thus tasks that have the lowest coefficients may end up with a zero margin. To prevent such a case and to distribute more evenly the total margin, we suggest to extend this model adding a constraint that imposes an upper bound on the margin value calculated for every task. This extension leads to the LP-FairMargin model. We show then, that the LP-FairMargin model assigns tasks among the processors more evenly than LP-MaxMargin.
BibTeX:
@inproceedings{Trabelsi2012,
  author = {Trabelsi, Kods and Fauberteau, Frédéric},
  title = {Margin--Aware Partitioning for Real-Time Multiprocessor Systems},
  booktitle = {Proceedings of the 6th Junior Researcher Workshop on Real--Time Computing (JRWRTC)},
  year = {2012},
  pages = {7--12},
  url = {papers/Trabelsi2012.pdf}
}
Traore, K., Grolleau, E., Rahni, A. and Richard, M. Response--Time Analysis of tasks with offsets 2009 Proceedings of the 11th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA), pp. 1-8  inproceedings DOI URL 
Abstract: This article presents some results about schedulability analysis of tasks with offsets also known as transactions, in the particular case of monotonic transactions. The impact of a transaction on the response time of a lower priority task under analysis is computed with the interference implied by the transaction. In the general context of tasks with offsets (general transactions), only exponential methods are known to calculate the exact worst--case response time of a task. However, in this case, Maki-Turja and Nolin have proposed an efficient approximation method. A monotonic pattern in a transaction (regarding the priority of the task under analysis), occurs when, by rotation of the higher priority tasks in a transaction, it is possible to find a pattern of tasks such that the processor demand of the transaction is monotically decreasing during a period of the transaction. We have shown in our previous work that if a task under analysis is such that all the interfering transactions are monotonic, then it is possible to evaluate its exact response time in a pseudo-polynomial time. This article presents in detail how to apply this method. Then, it compares our results to the multiframe model proposed by Mok and Chen in (1996) (AM "accumulatively monotonic" pattern). We show that the multiframe model is a particular instance of tasks with offsets but the results presented for AM multiframe cannot be applied on monotonic transactions. Finally, we show that the approximation method proposed by Maki-Turja and Nolin computes an exact response time in the case of monotonic transactions, even if its complexity is higher than the one of the test that we proposed.
BibTeX:
@inproceedings{Traore2009,
  author = {Traore, Karim and Grolleau, Emmanuel and Rahni, Ahmed and Richard, Michaël},
  title = {Response--Time Analysis of tasks with offsets},
  booktitle = {Proceedings of the 11th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA)},
  publisher = {IEEE Computer Society},
  year = {2009},
  pages = {1--8},
  url = {papers/Traore2006.pdf},
  doi = {http://doi.org/10.1109/ETFA.2006.355182}
}
Velasco, M., Martí, P. and Fuertes, J.M. The self triggered task model for real--time control systems 2003 Proceedings of the Work--in-Progress Session of the 24th IEEE Real-Time Systems Symposium (WiP RTSS), pp. 67-70  inproceedings URL 
Abstract: In this paper we present a control--based model for control tasks that allows each control task to trigger itself optimizing computing resources and control performance. Using this model, at each control task instance execution, the executing instance informs the scheduler when the next instance should be executed. The next instance execution point in time is dynamically obtained as a function of the utilization factor and control performance. Preliminary results show that control activities, at run time, are able to define self-execution patterns that dynamically balance optimal levels of control performance and resource utilization.
BibTeX:
@inproceedings{Velasco2003,
  author = {Velasco, Manel and Martí, Pau and Fuertes, Josep M.},
  title = {The self triggered task model for real--time control systems},
  booktitle = {Proceedings of the Work--in-Progress Session of the 24th IEEE Real-Time Systems Symposium (WiP RTSS)},
  year = {2003},
  pages = {67--70},
  url = {papers/Velasco2003.pdf}
}
Verbeek, F., Havle, O., Schmaltz, J., Tverdyshev, S., Blasum, H., Langenstein, B., Stephan, W., Wolff, B. and Nemouchi, Y. Formal API Specification of the PikeOS Separation Kernel 2015 NASA Formal Methods: 7th International Symposium, NFM 2015, Pasadena, CA, USA, April 27-29, 2015, Proceedings, pp. 375-389  inbook DOI URL 
Abstract: PikeOS is an industrial operating system for safety and security critical applications in, for example, avionics and automotive contexts. A consortium of several European partners from industry and academia works on the certification of PikeOS up to at least Common Criteria EAL5+, with ``+'' being applying formal methods compliant up to EAL7. We have formalized the hardware independent security-relevant part of PikeOS that is to be used in a certification context. Over this model, intransitive noninterference has been proven. We present the model and the methodology used to create the model. All results have been formalized in the Isabelle/HOL theorem prover.
BibTeX:
@inbook{Verbeek2015,
  author = {Verbeek, Freek and Havle, Oto and Schmaltz, Julien and Tverdyshev, Sergey and Blasum, Holger and Langenstein, Bruno and Stephan, Werner and Wolff, Burkhart and Nemouchi, Yakoub},
  title = {Formal API Specification of the PikeOS Separation Kernel},
  booktitle = {NASA Formal Methods: 7th International Symposium, NFM 2015, Pasadena, CA, USA, April 27-29, 2015, Proceedings},
  publisher = {Springer International Publishing},
  year = {2015},
  pages = {375--389},
  url = {http://dx.doi.org/10.1007/978-3-319-17524-9_26},
  doi = {http://doi.org/10.1007/978-3-319-17524-9_26}
}
Vestal, S. Preemptive Scheduling of Multi--criticality Systems with Varying Degrees of Execution Time Assurance 2007 Proceedings of the 28th IEEE International Real--Time Systems Symposium (RTSS), pp. 239-243  inproceedings DOI URL 
Abstract: This paper is based on a conjecture that the more confidence one needs in a task execution time bound (the less tolerant one is of missed deadlines), the larger and more conservative that bound tends to become in practice. We assume different tasks perform functions having different criticalities and requiring different levels of assurance. We assume a task may have a set of alternative worst--case execution times, each assured to a different level of confidence. This paper presents ways to use this information to obtain more precise schedulability analysis and more efficient preemptive fixed priority scheduling. These methods are evaluated using workloads abstracted from production avionics systems.
BibTeX:
@inproceedings{Vestal2007,
  author = {Vestal, Steve},
  title = {Preemptive Scheduling of Multi--criticality Systems with Varying Degrees of Execution Time Assurance},
  booktitle = {Proceedings of the 28th IEEE International Real--Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {239--243},
  url = {papers/Vestal2007.pdf},
  doi = {http://doi.org/10.1109/RTSS.2007.47}
}
Vestal, S. Fixed--priority sensitivity analysis for linear compute time models 1994 IEEE Transactions on Software Engineering
Vol. 20(4), pp. 308-317 
article DOI URL 
Abstract: Several formal results exist that allow an analytic determination of whether a particular scheduling discipline can feasibly schedule a given set of hard real--time periodic tasks. In most cases, these results provide little more than a `yes' or `no' answer. In practice, it is also useful to know how sensitive scheduling feasibility is to changes in the characteristics of the task set. This paper presents algorithms that allow a system developer to determine, for fixed-priority preemptive scheduling of hard real-time periodic tasks on a uniprocessor, how sensitive schedule feasibility is to changes in the computation times of various software components. The algorithms allow a system developer to determine what changes in task computation times can be made while preserving schedule feasibility (or what changes are needed to achieve feasibility). Both changes to the computation time of a single task and changes to the computation times of a specified subset of the tasks are analyzable. The algorithms also allow a decomposition of tasks into modules, where a module may be a component of multiple tasks.
BibTeX:
@article{Vestal1994,
  author = {Vestal, Steve},
  title = {Fixed--priority sensitivity analysis for linear compute time models},
  journal = {IEEE Transactions on Software Engineering},
  year = {1994},
  volume = {20},
  number = {4},
  pages = {308--317},
  url = {papers/Vestal1994.pdf},
  doi = {http://doi.org/10.1109/32.277577}
}
Wang, S., Wang, D., Su, L., Kaplan, L.M. and Abdelzaher, T.F. Towards Cyber--Physical Systems in Social Spaces: The Data Reliability Challenge 2014 Proceedings of the 35th IEEE Real-Time Systems Symposium (RTSS), pp. 74-85  inproceedings DOI URL 
Abstract: Today’s cyber--physical systems (CPS) increasingly operate in social spaces. Examples include transportation systems, disaster response systems, and the smart grid, where humans are the drivers, survivors, or users. Much information about the evolving system can be collected from humans in the loop; a practice that is often called crowd-sensing. Crowd-sensing has not traditionally been considered a CPS topic, largely due to the difficulty in rigorously assessing its reliability. This paper aims to change that status quo by developing a mathematical approach for quantitatively assessing the probability of correctness of collected observations (about an evolving physical system), when the observations are reported by sources whose reliability is unknown. The paper extends prior literature on state estimation from noisy inputs, that often assumed unreliable sources that fall into one or a small number of categories, each with the same (possibly unknown) background noise distribution. In contrast, in the case of crowd-sensing, not only do we assume that the error distribution is unknown but also that each (human) sensor has its own possibly different error distribution. Given the above assumptions, we rigorously estimate data reliability in crowd-sensing systems, hence enabling their exploitation as state estimators in CPS feedback loops. We first consider applications where state is described by a number of binary variables, then extend the approach trivially to multivalued variables. The approach also extends prior work that addressed the problem in the special case of systems whose state does not change over time. Evaluation results, using both simulation and a real-life case-study, demonstrate the accuracy of the approach.
BibTeX:
@inproceedings{Wang2014,
  author = {Wang, Shiguang and Wang, Dong and Su, Lu and Kaplan, Lance M. and Abdelzaher, Tarek F.},
  title = {Towards Cyber--Physical Systems in Social Spaces: The Data Reliability Challenge},
  booktitle = {Proceedings of the 35th IEEE Real-Time Systems Symposium (RTSS)},
  publisher = {IEEE Computer Society},
  year = {2014},
  pages = {74--85},
  url = {papers/Wang2014.pdf},
  doi = {http://doi.org/10.1109/RTSS.2014.19}
}
Wang, S., Wang, Y.-C. and Lin, K.-J. Integrating Priority with Share in the Priority-Based Weighted Fair Queuing Scheduler for Real-Time Networks 2002 Real-Time Systems
Vol. 22(1), pp. 119-149 
article DOI URL 
Abstract: The Weighted Fair Queuing (WFQ) scheduler has been closely studied due to its desirable properties of bandwidth guarantee and bounded delay. However, the queuing delay bound of a communication session is tightly coupled with the session's allocated service share. To receive a low queuing delay, a session must reserve a high share. In this paper, we study a new fair queuing algorithm called Priority-based Weighted Fair Queuing (PWFQ). PWFQ combines a session's allocated share to achieve the bandwidth guarantee and the session's priority to adjust the delay bound inside a sliding window. The new algorithm decouples the delay from the service share so that a session with a low share but a high priority may still receive a small delay. We analyze the worst-case delay bound of PWFQ and propose a simple algorithm to assign session priorities.
BibTeX:
@article{Wang2002,
  author = {Wang, Song and Wang, Yu-Chung and Lin, Kwei-Jay},
  title = {Integrating Priority with Share in the Priority-Based Weighted Fair Queuing Scheduler for Real-Time Networks},
  journal = {Real-Time Systems},
  year = {2002},
  volume = {22},
  number = {1},
  pages = {119--149},
  url = {/papers/Wang2002.pdf},
  doi = {http://doi.org/10.1023/A:1013485520989}
}
Ward, B.C. and Anderson, J.H. Fine--Grained Multiprocessor Real-Time Locking with Improved Blocking 2013 Proceedings of the 21st International Conference on Real--Time Networks and Systems (RTNS), pp. 67-76  inproceedings URL 
Abstract: Existing multiprocessor real--time locking protocols that support nesting are subject to adverse blocking that can be avoided when additional resource-usage-pattern information is known. These sources of blocking stem from system overheads, varying critical section lengths, and a lack of support for replicated resources. In this paper, these issues are resolved in the context of the recently proposed real-time nested locking protocol (RNLP). The resulting protocols are the first to support fine-grained real-time lock nesting while allowing multiple resources to be locked in one atomic operation, both spin- and suspension-based waiting to be used together, and resources to be replicated. They also reduce short-on-long” blocking, which is very detrimental if both very long and very short critical sections must be supported.
BibTeX:
@inproceedings{Ward2013,
  author = {Ward, Bryan C. and Anderson, James H.},
  title = {Fine--Grained Multiprocessor Real-Time Locking with Improved Blocking},
  booktitle = {Proceedings of the 21st International Conference on Real--Time Networks and Systems (RTNS)},
  publisher = {ACM},
  year = {2013},
  pages = {67--76},
  url = {papers/Ward2013.pdf}
}
Ward, B.C. and Anderson, J.H. Supporting Nested Locking in Multiprocessor Real--Time Systems 2012 Proceedings of the 24th Euromicro Conference on Real--Time Systems (ECRTS), pp. 223-232  inproceedings DOI URL 
Abstract: This paper presents the first real--time multiprocessor locking protocol that supports fine-grained nested resource requests. This locking protocol relies on a novel technique for ordering the satisfaction of resource requests to ensure a bounded duration of priority inversions for nested requests. This technique can be applied on partitioned, clustered, and globally scheduled systems in which waiting is realized by either spinning or suspending. Furthermore, this technique can be used to construct fine-grained nested locking protocols that are efficient under spin-based, suspension-oblivious or suspension-aware analysis of priority inversions. Locking protocols built upon this technique perform no worse than coarse-grained locking mechanisms, while allowing for increased parallelism in the average case (and, depending upon the task set, better worst-case performance).
BibTeX:
@inproceedings{Ward2012,
  author = {Ward, Bryan C. and Anderson, James H.},
  title = {Supporting Nested Locking in Multiprocessor Real--Time Systems},
  booktitle = {Proceedings of the 24th Euromicro Conference on Real--Time Systems (ECRTS)},
  publisher = {IEEE Computer Society},
  year = {2012},
  pages = {223--232},
  url = {papers/Ward2012.pdf},
  doi = {http://doi.org/10.1109/ECRTS.2012.17}
}
Wei, H.-W., Chao, Y.-H., Lin, S.-S., Lin, K.-J. and Shih, W.-K. Current Results on EDZL Scheduling for Multiprocessor Real--Time Systems 2007 Proceedings of the 13th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA), pp. 120-130  inproceedings DOI URL 
Abstract: Many optimal uniprocessor schedulers, such as Earliest Deadline First (EDF) and Rate Monotonic (RM), do not have a good schedulability bound on multiprocessor systems. In this paper, we study an on--line algorithm Earliest Deadline First until Zero laxity (EDZL) for multiprocessor systems. A set of tasks scheduled by EDZL is scheduled using EDF until a job experiences a zero laxity. To avoid the job from missing its deadline, the priority of the job is immediately promoted to the highest priority. We derive the schedulability bound of 3/2+|umax–1/2| for two-processor systems, where umax is the maximum utilization of an individual task in the given task set. We also discuss the best known upper bound and lower bound on EDZL schedulability conditions.
BibTeX:
@inproceedings{Wei2007,
  author = {Wei, Hsin--Wen and Chao, Yi-Hsiung and Lin, Shun-Shii and Lin, Kwei-Jay and Shih, Wei-Kuan},
  title = {Current Results on EDZL Scheduling for Multiprocessor Real--Time Systems},
  booktitle = {Proceedings of the 13th IEEE International Conference on Embedded and Real--Time Computing Systems and Applications (RTCSA)},
  publisher = {IEEE Computer Society},
  year = {2007},
  pages = {120--130},
  url = {papers/Wei2007.pdf},
  doi = {http://doi.org/10.1109/RTCSA.2007.34}
}
Wei, Y.-H., Leng, Q., Han, S., Mok, A.K., Zhang, W. and Tomizuka, M. RT-WiFi: Real-Time High-Speed Communication Protocol for Wireless Cyber-Physical Control Applications 2013 Proceedings of the 34th IEEE Real-Time Systems Symposium (RTSS), pp. 140-149  inproceedings DOI  
Abstract: Applying wireless technologies in control systems can significantly enhance