Youcheng Sun

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In this paper we address the problem of schedulability analysis for a set of sporadic tasks with arbitrary deadlines running on a multiprocessor system with global fixed-priority preemptive scheduling. We prove the existence of a class of critical instants for releasing a task, one of which results in the worst-case response time of that task. Then, we(More)
In this paper we present an exact schedulability test for sporadic real-time tasks scheduled by the Global Fixed Priority (G-FP) Fully Preemptive Scheduler on a multiprocessor system. The analysis consists in modelling the system as a Linear Hybrid Automaton, and in performing a reachability analysis for states representing deadline miss conditions. To(More)
We address the problem of schedulability analysis for a set of sporadic real-time tasks scheduled by the Global Earliest Deadline First (G-EDF) policy on a multiprocessor platform. State-of-the-art tests for schedulability analysis of multiprocessor global scheduling are often incomparable. That is, a task set that is judged not schedulable by a test may be(More)
We propose here a framework to model real-time components consisting of concurrent real-time tasks running on a single processor, using parametric timed automata. Our framework is generic and modular, so as to be easily adapted to different schedulers and more complex task models. We first perform a parametric schedulability analysis of the components using(More)
Formal methods (e.g. Timed Automata or Linear Hybrid Automata) can be used to analyse a real-time system by performing a reachability analysis on the model. The advantage of using formal methods is that they are more expressive than classical analytic models used in schedulability analysis. For example, it is possible to express state-dependent behaviour,(More)
In this paper, we address the problem of parametric schedulability analysis of distributed real-time systems scheduled by fixed priority. We propose two different approaches to parametric analysis. The first one is a novel analytic technique that extends single-processor sensitivity analysis to the case of distributed systems. The second approach is based(More)
Multicores are today used in automotive, controls and avionics systems supporting real-time functionality. When real-time tasks allocated on different cores cooperate through the use of shared communication resources, they need to be protected by mechanisms that guarantee access in a mutual exclusive way with bounded worst-case blocking time. Lock-based(More)
In this paper we present an exact schedulability test for sporadic real-time tasks scheduled by the Global Fixed Priority Fully Preemptive Scheduler on a multiprocessor system. The analysis consists in modeling the system as a Linear Hybrid Automaton, and in performing a reachability analysis for states representing deadline miss conditions. To mitigate the(More)
When integrating hard, soft and non-real-time tasks in general purpose operating systems, it is necessary to provide temporal isolation so that the timing properties of one task do not depend on the behaviour of the others. However, strict budget enforcement can lead to inefficient use of the computational resources in the presence of tasks with variable(More)
Formal methods (e.g. Timed Automata or Linear Hybrid Automata) can be used to analyse a real-time system by performing a reachability analysis on the model. The advantage of using formal methods is that they are more expressive than classical analytic models used in schedulability analysis. For example, it is possible to express state-dependent behaviour,(More)