An extendible approach for analyzing fixed priority hard real-time tasks

Tindell, K.; Burns, Alan; Wellings, Andy

doi:10.1007/bf01088593

Cited by 423 publications

(318 citation statements)

References 13 publications

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“…This involves more complex schedulability analysis, because higher-priority jobs suspend (preempt) the execution of lower-priority jobs in response to externallygenerated events [Audsley et al 1993;Tindell et al 1994]. For our example, foo is assigned a higher priority, and when it becomes runnable at 2ms, it preempts bar.…”

Section: Real-time Systems Sharing the Cpumentioning

confidence: 99%

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Explicit reservation of cache memory in a predictable, preemptive multitasking real-time system

Whitham

Audsley

Davis

2014

ACM Trans. Embed. Comput. Syst.

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We describe and evaluate explicit reservation of cache memory to reduce the cache-related preemption delay (CRPD) observed when tasks share a cache in a preemptive multitasking hard real-time system. We demonstrate the approach using measurements obtained from a hardware prototype, and present schedulability analyses for systems that share a cache by explicit reservation. These analyses form the basis for a series of experiments to further evaluate the approach. We find that explicit reservation is most useful for larger task sets with high utilization. Some task sets cannot be scheduled with a conventional cache, but are schedulable with explicit reservation.

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Section: Real-time Systems Sharing the Cpumentioning

confidence: 99%

“…In this section, we extend the schedulability analysis given by [Tindell et al 1994] for fixed priority preemptive scheduling of tasks with arbitrary deadlines to account for the initial and final non-preemptive phases in our task model. We provide an exact test valid for tasks with arbitrary deadlines.…”

Section: Exact Schedulability Testmentioning

confidence: 99%

Explicit reservation of cache memory in a predictable, preemptive multitasking real-time system

Whitham

Audsley

Davis

2014

ACM Trans. Embed. Comput. Syst.

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“…For static priority preemptively scheduled systems such as rate monotonic, we use response time analyses [Joseph and Pandya 1986;Tindell et al 1994] to obtain a necessary and sufficient condition. For a task T i , the idea is to consider all preemptions produced by higher priority tasks on an increasing window time.…”

Section: Task Model and Schedulability Analysismentioning

confidence: 99%

Data cache locking for tight timing calculations

Vera

Lisper

Xue

2007

ACM Trans. Embed. Comput. Syst.

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Caches have become increasingly important with the widening gap between main memory and processor speeds. Small and fast cache memories are designed to bridge this discrepancy. However, they are only effective when programs exhibit sufficient data locality. In addition, caches are a source of unpredictability, resulting in programs sometimes behaving in a different way than expected.Detailed information about the number of cache misses and their causes allows us to predict cache behavior and to detect bottlenecks. Small modifications in the source code may change memory patterns, thereby altering the cache behavior. Code transformations which take the cache behavior into account might result in a high cache performance improvement. However, cache memory behavior is very hard to predict, thus making the task of optimizing and timing cache behavior very difficult.This article proposes and evaluates a new compiler framework that times cache behavior for multitasking systems. Our method explores the use of cache partitioning and dynamic cache locking to provide worst-case performance estimates in a safe and tight way for multitasking systems. We use cache partitioning, which divides the cache among tasks to eliminate inter-task cache interferences. We combine static cache analysis and cache locking mechanisms to ensure that all intra-task conflicts, and consequently, memory access times, are exactly predictable.The results of our experiments demonstrate the capability of our framework to describe cache behavior at compile time. We compare our timing approach with a system equipped with a nonpartitioned but statically locked data cache. Our method outperforms static cache locking for all analyzed task sets under various cache architectures, demonstrating that our fully predictable scheme does not compromise the performance of the transformed programs.

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“…After that ®rst fundamental contribution, much work has been done for dealing with periodic tasks with deadlines less than periods [1,26,3]. In particular, the``processor demand approach'', proposed in Ref.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, several aperiodic service mechanisms have been proposed under RM www.elsevier.com/locate/sysarc Journal of Systems Architecture 46 (2000) 327±338 [12,13,1,26] and under EDF [20,9,22,23], but no resource constraints have been taken into account. In Ref.…”

Section: Introductionmentioning

confidence: 99%

Schedulability analysis of periodic and aperiodic tasks with resource constraints

Lipari

Buttazzo

2000

Journal of Systems Architecture

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In this paper, we address the problem of scheduling hybrid task sets consisting of hard periodic and soft aperiodic tasks that may share resources in exclusive mode in a dynamic environment, where tasks are scheduled based on their deadlines. Bounded blocking on exclusive resources is achieved by means of a dynamic resource access protocol which also prevents deadlocks and chained blocking. Aperiodic responsiveness is enhanced by an e cient servicing technique which assigns each aperiodic request a suitable deadline. Feasibility conditions are extended to handle tasks with deadlines di erent from periods and a reclaiming technique is presented to deal with early completions. Ó

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An extendible approach for analyzing fixed priority hard real-time tasks

Cited by 423 publications

References 13 publications

Explicit reservation of cache memory in a predictable, preemptive multitasking real-time system

Explicit reservation of cache memory in a predictable, preemptive multitasking real-time system

Data cache locking for tight timing calculations

Schedulability analysis of periodic and aperiodic tasks with resource constraints

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