Skip to Main content Skip to Navigation
Conference papers

A Stretching Algorithm for Parallel Real-time DAG Tasks on Multiprocessor Systems

Abstract : Parallelism is becoming more important nowadays due to the increasing use of multiprocessor systems. In this paper, we study the problem of scheduling periodic parallel real-time Directed Acyclic graph (DAG) tasks on m homogeneous multiprocessor systems. A DAG task is an example of inter-subtask parallelism. It consists of a collection of dependent subtasks under precedence constraints. The dependencies between subtasks make scheduling process more challenging. We propose a stretching algorithm applied on each DAG tasks to transform them into a set of independent sequential threads with intermediate offsets and deadlines. The threads obtained with the transformation are two types, (i) fully-stretched master threads with utilization equal to 1 and (ii) constrained-deadline independent threads. The fully-stretched master threads are assigned to dedicated processors and the remaining processors m' ≤ m, are scheduled using global EDF scheduling algorithm. Then, we prove that preemptive global EDF scheduling of stretched threads has a resource augmentation bound equal to (3+ √ 5)/2 for all tasksets with n < ϕ * m , where n is the number of tasks in the taskset and ϕ is the golden ratio 1 .
Complete list of metadatas

Cited literature [12 references]  Display  Hide  Download
Contributor : Manar Qamhieh <>
Submitted on : Wednesday, December 3, 2014 - 6:36:19 PM
Last modification on : Wednesday, February 26, 2020 - 7:06:07 PM
Long-term archiving on: : Monday, March 9, 2015 - 5:52:46 AM


Files produced by the author(s)



Manar Qamhieh, Laurent George, Serge Midonnet. A Stretching Algorithm for Parallel Real-time DAG Tasks on Multiprocessor Systems. The 22nd International Conference on Real-Time Networks and Systems, Oct 2014, Versaille, France. pp.13-22, ⟨10.1145/2659787.2659818⟩. ⟨hal-01090627⟩



Record views


Files downloads