Reliable mode changes in real-time systems with fixed priority or EDF scheduling

Stoimenov,; Perathoner,; Thiele,

doi:10.1109/date.2009.5090640

Cited by 38 publications

(32 citation statements)

References 9 publications

(14 reference statements)

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“…Research on uniprocessor multi-mode real-time systems can be divided into two categories: fixed-priority scheduling [11], [13], [20] and EDF scheduling [12], [17]. Tindell et al [21] introduced a simple protocol where newly-added tasks wait after a mode change until the processor completes the oldmode tasks.…”

Section: Related Workmentioning

confidence: 99%

“…Using RTC, Stoimenov et al [17], [18] and Santinelli et al [14] investigated schedulability of hardware modes and software modes separately; however, scenarios where both hardware and software must change modes were not addressed. One set of recent results by Phan et al [12] has addressed multiple hardware and software-level modes and proposed a sequential algorithm for schedulability analysis.…”

Section: Related Workmentioning

confidence: 99%

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A Parallel Algorithm for EDF-Schedulability Analysis of Multi-modal Real-Time Systems

Ahmed

Fisher

Grosu

2012

2012 IEEE International Conference on Embedded and Real-Time Computing Systems and Applications

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Abstract-Modern real-time embedded systems often require the capability of switching between operating modes to adapt in dynamically changing environments. The development of such real-time multi-modal systems fundamentally relies upon effective schedulability analysis. Recently, researchers have proposed serial schedulability analysis algorithms for multi-modal systems that account for mode changes at both software level (e.g., changing the set of executing tasks) and hardware level (e.g., changing the operating speed of a processor). However, these algorithms have high runtime complexity which limits their practical usage as schedulability analysis in system design-space exploration. In this paper, we design a parallel algorithm as an efficient solution to the problem of determining the schedulability of uniprocessor multi-modal real-time systems scheduled by EDF. By emphasizing a balanced workload distribution and restricting the number of synchronizations, our parallel algorithm achieves a nearperfect speedup observable both theoretically and experimentally. Experimental results show that the runtime of our parallel algorithm is very low even for systems with large number of modes, making it a tractable choice for design-space exploration of real-time multi-modal systems.

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Section: Related Workmentioning

confidence: 99%

Section: Related Workmentioning

confidence: 99%

A Parallel Algorithm for EDF-Schedulability Analysis of Multi-modal Real-Time Systems

Ahmed

Fisher

Grosu

2012

2012 IEEE International Conference on Embedded and Real-Time Computing Systems and Applications

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“…[23] further improves [22] by supporting any event stream model and it can handle both the earliest deadline first (EDF) and fixed priority (FP) scheduling of tasks.…”

Section: Mode Change Protocolsmentioning

confidence: 99%

Online Scheduling Switch for Maintaining Data Freshness in Flexible Real-Time Systems

Han

Chen

Xiong³

et al. 2009

2009 30th IEEE Real-Time Systems Symposium

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Abstract-Maintaining the temporal validity of real-time data is one of the crucial issues in a real-time database system. Past studies focus on designing algorithms to minimize imposed workload by a fixed set of update transactions while maintaining data freshness within validity intervals. In this paper we revisit this problem by investigating the cost of data freshness maintenance and online scheduling overhead in the presence of mode changes in real-time systems. We propose to apply periodic scheduling policies when the imposed update workload is low to maintain high data freshness. When the update workload becomes high, we propose to switch to more sophisticated algorithms to improve schedulability. In the latter case, not only each scheduling policy must be able to schedule the task set in the corresponding mode, temporal validity must also be maintained during the mode changes. To address this problem, two algorithms, named search-based switch (SBS) and adjustmentbased switch (ABS) are proposed to search for the proper switch point online. SBS checks the temporal validity at the beginning time slot of each idle period while ABS further relaxes this restriction through schedule adjustment. Our experimental results demonstrate the correctness and efficiency of these two algorithms. Our results also show that scheduling switch according to the runtime processor workload can significantly outperform a single fixed scheduling policy in terms of data freshness while incurring only limited online switch overhead.

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“…Stoimenov et al present in [5] a real-time analysis for systems that can change their mode of operation. Each mode is represented by a set of tasks, where each task is associated with an activation pattern, a best-case and worst-case execution 978-3-9815370-0-0/DATE13/ c 2013 EDAA time, and a deadline.…”

Section: Related Workmentioning

confidence: 99%

Sufficient Real-Time Analysis for an Engine Control Unit with Constant Angular Velocities

Pollex¹,

Feld²,

Slomka³

et al. 2013

Design, Automation &Amp; Test in Europe Conference &Amp; Exhibition (DATE), 2013

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Abstract-Engine control units in the automotive industry are particular challenging real-time systems regarding their real-time analysis. Some of the tasks of such an engine control unit are triggered by the engine, i.e. the faster the angular velocity of the engine, the more frequent the tasks are executed. Furthermore, the execution time of a task may vary with the angular velocity of the engine. As a result the worst case does not necessarily occur when all tasks are activated simultaneously. Hence this behavior cannot be addressed appropriately with the currently available real-time analysis methods. In this paper we make a first step towards a real-time analysis for an engine control unit. We present a sufficient real-time analysis assuming that the angular velocity of the engine is arbitrary but fixed.

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Reliable mode changes in real-time systems with fixed priority or EDF scheduling

Cited by 38 publications

References 9 publications

A Parallel Algorithm for EDF-Schedulability Analysis of Multi-modal Real-Time Systems

A Parallel Algorithm for EDF-Schedulability Analysis of Multi-modal Real-Time Systems

Online Scheduling Switch for Maintaining Data Freshness in Flexible Real-Time Systems

Sufficient Real-Time Analysis for an Engine Control Unit with Constant Angular Velocities

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