Improved multiprocessor global schedulability analysis

Baruah, Sanjoy; Bonifaci, Vincenzo; Marchetti-Spaccamela, Alberto; Stiller, Sebastian

doi:10.1007/s11241-010-9096-3

Cited by 42 publications

(37 citation statements)

References 14 publications

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“…Researchers have proven resource augmentation bounds, utilization bounds and capacity augmentation bounds. The best known resource bound for G-EDF for sequential tasks on a multiprocessor is 2 [7]; a capacity augmentation bound of 2 − 1 m + for small [14]. Partitioned EDF and versions partitioned static priority schedulers also provide a utilization bound of 2 [3,37].…”

Section: Related Workmentioning

confidence: 99%

Analysis of Federated and Global Scheduling for Parallel Real-Time Tasks

Chen

Agrawal

et al. 2014

2014 26th Euromicro Conference on Real-Time Systems

175

119

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This paper considers the scheduling of parallel realtime tasks with implicit deadlines. Each parallel task is characterized as a general directed acyclic graph (DAG). We analyze three different real-time scheduling strategies: two well known algorithms, namely global earliestdeadline-first and global rate-monotonic, and one new algorithm, namely federated scheduling. The federated scheduling algorithm proposed in this paper is a generalization of partitioned scheduling to parallel tasks. In this strategy, each high-utilization task (utilization ≥ 1) is assigned a set of dedicated cores and the remaining low-utilization tasks share the remaining cores. We prove capacity augmentation bounds for all three schedulers. In particular, we show that if on unit-speed cores, a task set has total utilization of at most m and the criticalpath length of each task is smaller than its deadline, then federated scheduling can schedule that task set on m cores of speed 2; G-EDF can schedule it with speed 3+ √ 5 2 ≈ 2.618; and G-RM can schedule it with speed 2 + √ 3 ≈ 3.732. We also provide lower bounds on the speedup and show that the bounds are tight for federated scheduling and G-EDF when m is sufficiently large.

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Section: Related Workmentioning

confidence: 99%

Analysis of Federated and Global Scheduling for Parallel Real-Time Tasks

Chen

Agrawal

et al. 2014

2014 26th Euromicro Conference on Real-Time Systems

175

119

View full text Add to dashboard Cite

show abstract

“…In particular, for implicit deadline hard real-time tasks, the best known utilization bound is ≈ 50% using partitioned fixed priority scheduling [5] and partitioned EDF [6]; this trivially implies a capacity augmentation bound of 2. In comparison, GEDF has a capacity augmentation bound of 2 − 1 m + for small [7,8].…”

Section: Related Workmentioning

confidence: 99%

Federated scheduling for stochastic parallel real-time tasks

Agrawal

Gill

et al. 2014

2014 IEEE 20th International Conference on Embedded and Real-Time Computing Systems and Applications

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Abstract-Federated scheduling is a strategy to schedule parallel real-time tasks: It allocates a dedicated cluster of cores to each high-utilization task (utilization ≥ 1); It uses a multiprocessor scheduling algorithm to schedule and execute all low-utilization tasks sequentially, on a shared cluster of the remaining cores. Prior work has shown that federated scheduling has the best known capacity augmentation bound of 2 for parallel tasks with implicit deadlines. In this paper, we explore the soft realtime performance of federated scheduling and address averagecase workloads instead of worst-case ones. In particular, we consider stochastic tasks -tasks for which execution time and critical-path length are random variables. In this case, we use bounded expected tardiness as the schedulability criterion. We define a stochastic capacity augmentation bound and prove that federated scheduling algorithms guarantee the same bound of 2 for stochastic tasks. We present three federated mapping algorithms with different complexities for core allocation. All of them guarantee bounded expected tardiness and provide the same capacity augmentation bound. In practice, however, we expect them to provide different performance, both in terms of the task sets they can schedule and the actual tardiness they guarantee. Therefore, we present numerical evaluations using randomly generated task sets to examine the practical differences between the three algorithms.

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“…The authors of [SSL89] presented the Sporadic Server algorithm for scheduling aperiodic independent tasks, and showed the improvement of response times for the tasks with soft-deadlines as well as the guarantees of deadline satisfactions of tasks with hard-deadlines. The authors of [BBMSS10] presented the schedulability tests for global EDF and deadline monotonic policies on multiprocessor platforms. The authors of [AEP15] studied the influence of jitter on stability of real-time control applications, and presented an on-line scheduling policy to limit task response time variations, and thus, to guarantee stability of the control application.…”

Section: Timelinessmentioning

confidence: 99%

Security-Driven Design of Real-Time Embedded Systems

Jiang¹

2016

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R eal-time embedded systems (RTESs) have been widely used in modern society. And it is also very common to find them in safety and security critical applications, such as transportation and medical equipment. There are, usually, several constraints imposed on a RTES, for example, timing, resource, energy, and performance, which must be satisfied simultaneously. This makes the design of such systems a difficult problem.More recently, the security of RTESs emerges as a major design concern, as more and more attacks have been reported. However, RTES security, as a parameter to be considered during the design process, has been overlooked in the past. This thesis approaches the design of secure RTESs focusing on aspects that are particularly important in the context of RTES, such as communication confidentiality and side-channel attack resistance.Several techniques are presented in this thesis for designing secure RTESs, including hardware/software co-design techniques for communication confidentiality on distributed platforms, a global framework for secure multi-mode real-time systems, and a scheduling policy for thwarting differential power analysis attacks.All the proposed solutions have been extensively evaluated in a large amount of experiments, including two real-life case studies, which demonstrate the efficiency of the presented techniques.The research presented in this thesis has been funded by CUGS (the National Graduate School in Computer Science in Sweden) and VR (the Swedish Research Council).v Populärvetenskaplig Sammanfattning I nbyggda realtidssystem används idag i stor utsträckning i vårt moderna samhälle. Detär mycket vanligt att hitta dem i säker-hetskritiska tillämpningar såsom transport-och medicinsk utrustning. Vanligtvis har inbyggda realtidssystem flera designbegränsningar och krav gällande till exempel timing, resurser, energi och prestanda, som måste vara uppfyllda samtidigt. Detta gör utformningen av sådana system till ett mycket svårt problem.Under senare tid har säkerheten i inbyggda realtidssystem blivit en viktig konstruktionsaspekt eftersom fler och fler attacker har rapporterats. Tidigare har säkerhetskraven i inbyggda realtidssystem inte betraktats som designparametrar under själva designprocessen. Denna avhandling fokuserar bland annat på utformningen av säkra inbyggda system, huvudsakligen på aspekter somär särskilt viktiga i samband med realtidssystem, till exempel kommunikationssekretess och motstånd mot sidokanalattacker.I denna avhandling presenteras tre olika tekniker för att utforma säkra inbyggda realtidssystem. Först en teknik för hård-och mjukvaru co-design för kommunikationssekretess för distribuerade plattformar, sedan ett globalt ramverk för säkra multi-mode system och slutligen en schemaläggningspolicy för motstånd mot sidokanalattacker.Samtliga de föreslagna lösningarna har utvärderats i stor omfattning med en stor mängd experiment, inklusive två fallstudier som visar effektiviteten hos de presenterade teknikerna.vii

show abstract

Improved multiprocessor global schedulability analysis

Cited by 42 publications

References 14 publications

Analysis of Federated and Global Scheduling for Parallel Real-Time Tasks

Analysis of Federated and Global Scheduling for Parallel Real-Time Tasks

Federated scheduling for stochastic parallel real-time tasks

Security-Driven Design of Real-Time Embedded Systems

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