SMARTS
Slack Management in Hierarchical Real-Time Systems
| FCOMP-01-0124-FEDER-020536 PTDC/EIA-CCO/121904/2010 42 months (Apr 2012 to Sep 2015) | |
| Summary: | Most of modern computing systems are embedded with the physical environment. When such embedded systems are
additionally subject to temporal constraints they are termed real-time systems. There are a number of relevant trends in
real-time systems: The complexity of such systems increases dramatically, often leading to integration of subsystems from
various vendors; Real-time and best effort applications may share the processor on a given device; The software on such
systems may be subject to change leading to dynamic real-time systems.
A widely accepted design paradigm for such complex systems is component-based engineering in which 1) the system is first
decomposed into simpler and smaller applications, 2) applications are independently designed and analysed, and 3)
applications are composed together to generate the system. Depending on how the applications are grouped together for composition, the resulting system can be represented as a tree of applications; each parent-children pair denotes a composition where the child-applications were composed together to form the parent-application. Existing solutions to address real-time requirements of such applications are mainly restricted to offline techniques. A common way to describe the interfaces used for hierarchical systems are servers, which abstract the internal behaviour of the application and present a common interface to the parent scheduler. The parent scheduler schedules the servers of its child applications. Preemptions have a substantial impact on the system, as they cause, for example, the loss of working set in the caches. A further advantage of periodic servers is the possibility of choosing server parameters in the system in such a way, as to minimise the number of preemptions and thus increasing the performance of a system. Slack is execution time which is not used in a system. Slack in conventional systems may be categorised in two classes: 1) Static slack that is spare capacity available in the system, as the system is not loaded less than what can be guaranteed by the schedulability test; 2) dynamic slack caused by the difference between worst-case assumptions made in the analysis and the actual behaviour of the system at a given point in time. A fundamental challenge of hierarchical systems is that the abstraction provided by periodic servers is the source of additional slack. This is caused by the compositional separation of concerns, by avoiding the requirement of aglobal view of the system. Within this project we propose to investigate a comprehensive reclamation of all slack in a hierarchical system. This covers the identification of slack, at analysis and run time, as well as the efficient distribution of the identified slack while maintaining the temporal guarantees provided. Furthermore both the choice of server parameters (i.e. period and capacity) and the distribution of static slack has impact on the real-time analysis as well as the additional cost of preemption at run-time. We will investigate the impact of preemption, integrate pre-emption estimation techniques and provide a framework for alternative policies. Finally we will explore how the developed techniques can be applied in a multicore setting. For this we will build on the work of the ViPCore project (PTDC/EIA-CCO/111799/2009) also executed in CISTER, which in turn builds in among other things on [11, 27]. The multicore development will run in parallel to the other activities once the initial work on uniprocessors have been identified. |
| Funding: | Global: 158KEUR, CISTER: 158KEUR |
| Sponsors: |     |
| Partners: | |
| Contact Person at CISTER: | Stefan M. Petters |
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Journal Papers
Race-to-halt energy saving strategies CISTER-TR-150104
Muhammad Ali Awan, Stefan M. PettersJournal of Systems Architecture (JSA), Eelsevier. Nov 2014, Volume 60, Issue 10, pp 796-815.
Muhammad Ali Awan, Stefan M. PettersJournal of Systems Architecture (JSA), Eelsevier. Nov 2014, Volume 60, Issue 10, pp 796-815.
Dynamic cluster scheduling for cluster-tree WSNs CISTER-TR-140906
Ricardo Severino, Nuno Pereira, Eduardo TovarCommunication Networks, SpringerPlus. 31, Aug, 2014, Volume 3, Issue 493.
Ricardo Severino, Nuno Pereira, Eduardo TovarCommunication Networks, SpringerPlus. 31, Aug, 2014, Volume 3, Issue 493.
PDFConference or Workshop Papers/Talks
An Exact Schedulability Test for Global FP Using State Space Pruning CISTER-TR-150503
Artem Burmyakov, Enrico Bini, Eduardo Tovar23rd International Conference on Real-Time Networks and Systems (RTNS 2015). 4 to 6, Nov, 2015, Main Track. Lille, France.The software tool for the paper titled "An Exact Schedulability Test for Global FP Using State Space Pruning"
Artem Burmyakov, Enrico Bini, Eduardo Tovar23rd International Conference on Real-Time Networks and Systems (RTNS 2015). 4 to 6, Nov, 2015, Main Track. Lille, France.The software tool for the paper titled "An Exact Schedulability Test for Global FP Using State Space Pruning"
Zip ArchiveHard real-time multiprocessor scheduling resilient to core failures CISTER-TR-151105
Borislav Nikolic, Konstantinos Bletsas, Stefan M. Petters21st IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2015). 19 to 21, Aug, 2015, pp 122-131. Hong Kong, China.
Borislav Nikolic, Konstantinos Bletsas, Stefan M. Petters21st IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2015). 19 to 21, Aug, 2015, pp 122-131. Hong Kong, China.
EDF as an Arbitration Policy for Wormhole-Switched Priority-Preemptive NoCs - Myth or Fact? CISTER-TR-141006
Borislav Nikolic, Stefan M. PettersInternational Conference on Embedded Software (EMSOFT 2014). 12 to 17, Oct, 2014. New Delhi, India.
Borislav Nikolic, Stefan M. PettersInternational Conference on Embedded Software (EMSOFT 2014). 12 to 17, Oct, 2014. New Delhi, India.
Sufficient Temporal Independence and Improved Interrupt Latencies in a Real-Time Hypervisor CISTER-TR-140303
Matthias Beckert, Moritz Neukirchner, Rolf Ernst, Stefan M. PettersThe 51st Annual Design Automation Conference on Design Automation Conference (DAC '14). 1 to 5, Jun, 2014, pp 86:1-86:6. San Francisco, CA, U.S.A..
Matthias Beckert, Moritz Neukirchner, Rolf Ernst, Stefan M. PettersThe 51st Annual Design Automation Conference on Design Automation Conference (DAC '14). 1 to 5, Jun, 2014, pp 86:1-86:6. San Francisco, CA, U.S.A..
Towards Certifiable Adaptive Reservations for Hypervisor-based Virtualization CISTER-TR-140304
Stefan Groesbrink, Luís Almeida, Mario de Sousa, Stefan M. Petters20th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS 2014), IEEE. 15, Apr, 2014. Berlin, Germany.
Stefan Groesbrink, Luís Almeida, Mario de Sousa, Stefan M. Petters20th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS 2014), IEEE. 15, Apr, 2014. Berlin, Germany.
Worst-Case Communication Delay Analysis for Many-Cores using a Limited Migrative Model CISTER-TR-141002
Borislav Nikolic, Patrick Meumeu Yomsi, Stefan M. Petters20th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2014). 2014, Real-Time Systems Track. Chongqing, China.
Borislav Nikolic, Patrick Meumeu Yomsi, Stefan M. Petters20th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2014). 2014, Real-Time Systems Track. Chongqing, China.
Multiprocessor real-time scheduling with a few migrating tasks CISTER-TR-131204
José Augusto Santos Jr, George Lima, Konstantinos Bletsas, Shinpei Kato34th IEEE Real-Time Systems Symposium (RTSS 2013), IEEE. 3 to 6, Dec, 2013, pp 170-181. Vancouver, Canada.
José Augusto Santos Jr, George Lima, Konstantinos Bletsas, Shinpei Kato34th IEEE Real-Time Systems Symposium (RTSS 2013), IEEE. 3 to 6, Dec, 2013, pp 170-181. Vancouver, Canada.
Are Virtual Channels the Bottleneck of Priority-Aware Wormhole-Switched NoC-Based Many-Cores? CISTER-TR-130901
Borislav Nikolic, Hazem Ali, Stefan M. Petters, Luis Miguel Pinho21st International Conference on Real-Time Networks and Systems (RTNS 2013), ACM New York. 16 to 18, Oct, 2013, pp 13-22. Sophia Antipolis, France.
Borislav Nikolic, Hazem Ali, Stefan M. Petters, Luis Miguel Pinho21st International Conference on Real-Time Networks and Systems (RTNS 2013), ACM New York. 16 to 18, Oct, 2013, pp 13-22. Sophia Antipolis, France.
Worst-Case Memory Traffic Analysis for Many-Cores using a Limited Migrative Model CISTER-TR-130902
Borislav Nikolic, Patrick Meumeu Yomsi, Stefan M. Petters19th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2013), IEEE. 19 to 21, Aug, 2013, pp 42-51. Taipei, Taiwan.
Borislav Nikolic, Patrick Meumeu Yomsi, Stefan M. Petters19th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2013), IEEE. 19 to 21, Aug, 2013, pp 42-51. Taipei, Taiwan.
Fair Bandwidth Sharing among Virtual Machines in a Multi-criticality Scope CISTER-TR-130407
Stefan Groesbrink, Luís Almeida, Mario de Sousa, Stefan M. Petters5th Workshop on Adaptive and Reconfigurable Embedded Systems (APRES 2013), ACM New York. 8, Apr, 2013, 10, 4, pp 21-24. Philadelphia, U.S.A..
Stefan Groesbrink, Luís Almeida, Mario de Sousa, Stefan M. Petters5th Workshop on Adaptive and Reconfigurable Embedded Systems (APRES 2013), ACM New York. 8, Apr, 2013, 10, 4, pp 21-24. Philadelphia, U.S.A..
Using NPS-F for Mixed-Criticality Multicore Systems CISTER-TR-130303
Konstantinos Bletsas, Stefan M. Petters33rd IEEE Real-Time Systems Symposium (RTSS 2012), ACM. 4 to 7, Dec, 2012, Work-in-Progress Session, pp 36-36. San Juan, Puerto Rico.
Konstantinos Bletsas, Stefan M. Petters33rd IEEE Real-Time Systems Symposium (RTSS 2012), ACM. 4 to 7, Dec, 2012, Work-in-Progress Session, pp 36-36. San Juan, Puerto Rico.
Conference or Workshop Posters/Demos
Response Time Analysis for Fixed-Priority Tasks with Multiple Probabilistic Parameters CISTER-TR-150301
Dorin Maxim, Liliana Cucu-GrosjeanPoster presented in 12th Workshop on Models and Algorithms for Planning and Scheduling Problems (MAPSP 2015). 8 to 12, Jun, 2015. La Roche-en-Ardenne, Belgium.Extended abstract
Dorin Maxim, Liliana Cucu-GrosjeanPoster presented in 12th Workshop on Models and Algorithms for Planning and Scheduling Problems (MAPSP 2015). 8 to 12, Jun, 2015. La Roche-en-Ardenne, Belgium.Extended abstract