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Improved Response Time Analysis of Sporadic DAG Tasks for Global FP Scheduling
Ref: CISTER-TR-170901       Publication Date: 4 to 6, Oct, 2017

Improved Response Time Analysis of Sporadic DAG Tasks for Global FP Scheduling

Ref: CISTER-TR-170901       Publication Date: 4 to 6, Oct, 2017

Abstract:
One of the major sources of pessimism in the response time analysis of globally schedule d real-time tasks is the computation of the upper-bound on the inter-task interference. This problem is further exacerbated when intra-task parallelism is permitted, because of the complex internal structure of parallel tasks. This paper considers the global fie d-priority scheduling (G-FP) of sporadic real-time tasks, each one mo dele d by a directed acyclic graph (DAG) of parallel subtasks. We present a response time analysis technique based on the concept of problem window. We propose two novel techniques to derive tight upper-bounds on the workload produced by the carry-in and carry-out jobs of the interfering tasks, by taking into account the precedence constraints between their subtasks. We show that with these new upper-bounds, the proposed schedulability test does not only theoretically dominate state-of-the-art techniques but also offers significant improvements on the schedulability of DAG tasks for randomly generate d task sets.

Authors:
José Fonseca
,
Geoffrey Nelissen
,
Vincent Nélis


Accepted in International Conference on Real-Time Networks and Systems 2017 (RTNS 2017).
Grenoble, France.



Record Date: 8, Sep, 2017