An Exact Schedulability Test for Non-Preemptive Self-Suspending Real-Time Tasks

Yalcinkaya, Beyazit; Nasri, Mitra; Brandenburg, Björn B.

doi:10.23919/date.2019.8715111

Cited by 23 publications

(11 citation statements)

References 27 publications

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“…Obtaining the WCET of each task in real-time is the basis for the schedulability analysis. Different approaches have been studied for scheduling tasks in real-time multicore systems: partitioned [54], [175], semi-partitioned [176]- [178] and global [179]- [181] scheduling. In the partitioned scheduling approach, tasks are assigned between available processors, and each task can only be executed on the processor where it was assigned.…”

Section: Schedulability Analysis Techniquesmentioning

confidence: 99%

A Survey of Techniques for Reducing Interference in Real-Time Applications on Multicore Platforms

et al. 2022

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This survey reviews the scientific literature on techniques for reducing interference in real-time multicore systems, focusing on the approaches proposed between 2015 and 2020. It also presents proposals that use interference reduction techniques without considering the predictability issue. The survey highlights interference sources and categorizes proposals from the perspective of the shared resource. It covers techniques for reducing contentions in main memory, cache memory, a memory bus, and the integration of interference effects into schedulability analysis. Every section contains an overview of each proposal and an assessment of its advantages and disadvantages.INDEX TERMS Real-time systems, architecture, multicore, timing analysis, schedulability analysis, WCET, co-runner interference.

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Section: Schedulability Analysis Techniquesmentioning

confidence: 99%

A Survey of Techniques for Reducing Interference in Real-Time Applications on Multicore Platforms

et al. 2022

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“…The recent studies mainly focus on the schedulability analysis of other task models. They are self-suspended task model [36], restricted preemptive scheduling [37], DAG(Direct Acyclic Graph) task model [38] ,multi-core scheduling [39] and so on.…”

Section: Related Workmentioning

confidence: 99%

A Schedulability Test for Sporadic Task DM Scheduling Based on Density Upper Bound

Liu

Qiao

Yang³

et al. 2022

IEEE Access

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Due to low runtime overhead and simple implementation of DM(Deadline Monotonic) scheduling, it is widely used in real-time systems. Aiming at the schedulability test problem of the sporadic task DM(Deadline Monotonic) scheduling under uniprocessor, a density upper bound of 0.693 is analyzed, which can determine the schedulability of a task set in linear time. The theoretical analysis process is carried out in three steps. Firstly, the case is considered where the task set contains only two tasks and the deadline ratio between the tasks is less than 2. Secondly, the case is considered where the task set contains multiple tasks and the deadline ratio between any two tasks is still less than 2. Finally, the case is considered where the task set contains multiple tasks and the deadline ratio between tasks is an arbitrary value. The experimental results show that the upper bound of density is higher than related methods and the run time overhead is much lower than that of other available exact schedulability tests. The time complexity is O(1) when a task is dynamically added to the task set, while that of other methods increases rapidly along with the number of tasks. In addition, we combined this upper bound and other tests to further propose an exact schedulability test, which effectively reduces the running time overhead by 30.8% compared with the stateof-the-art schedulability test. Due to the high efficiency of our schedulability test, an online schedulability test can be implemented in open real-time systems.

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“…These studies differ in the underlying task models, the considered scheduling policies and the employed model-checking methods. The majority of works [49,13,43,12,10,50] use Timed Automata with UPPAAL as model-checker and some with Stopwatches. In contrast, the paper [23] uses of the symbolic model-checker nuSMV [11], while [31] uses an approach based on the transformation of time Petri nets into linear hybrid automaton and the verification of the transformed models with the HyTECH model-checker [25].…”

Section: Model-checking For Schedulabilitymentioning

confidence: 99%

“…Only [12] proposes different schedulers such as LLF and LLREF but this work is based on a deterministic task model and is quite similar to a simulator. More recently, [50] focuses on a non-preemptive policy with self-suspending tasks. Without surprise, papers that present experimental evaluations note scalability issues both in terms of the number of tasks and in relation to non-deterministic variables, i.e., variation in execution times, uncertainty about task starts, etc.…”

Section: Model-checking For Schedulabilitymentioning

confidence: 99%

Bridging the gap between formal verification and schedulability analysis: The case of robotics

Foughali

Hladik

2020

Journal of Systems Architecture

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The challenges of deploying robots and autonomous vehicles call for further efforts to bridge the gap between the robotics, the real-time systems and the formal methods communities. Indeed, with robots being more and more involved in costly missions and contact with humans, a rigorous formal verification of their behavior in the presence of various real-time constraints is crucial. In order to increase our trust in its results, such verification should be carried out on models that are as close as possible to reality, and thus take into account hardware and OS specificities such as the number of cores provided by the robotic platform and the scheduling policy. In this paper, we propose a novel binary-search-inspired technique that allows to extend timed automata models of robotic specifications with dynamic-priority schedulers. Given a number of cores, the extended models can then be checked against various real-time and behavioral properties, including schedulability, within the same model checking framework. Our technique is implemented in an automatic translation from a robotic framework to UPPAAL, and evaluated on a real robotic case study, where it shows a significant gain in scalability as opposed to the counting technique used in the literature.

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An Exact Schedulability Test for Non-Preemptive Self-Suspending Real-Time Tasks

Cited by 23 publications

References 27 publications

A Survey of Techniques for Reducing Interference in Real-Time Applications on Multicore Platforms

A Survey of Techniques for Reducing Interference in Real-Time Applications on Multicore Platforms

A Schedulability Test for Sporadic Task DM Scheduling Based on Density Upper Bound

Bridging the gap between formal verification and schedulability analysis: The case of robotics

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