Response-Time Analysis of Limited-Preemptive Sporadic DAG Tasks

Guaranteeing timing constraints for parallel real-time applications deployed on multicore platforms is challenging, especially for applications containing non-preemptive execution blocks, that suffer from priority inversions. In this article, we propose to model such applications using a sporadic directed acyclic graph (DAG) model where preemption may take place only between the nodes of a DAG task. We present a new method for response-time analysis of such tasks scheduled with the global fixed-priority scheduling policy. We show that our method outperforms the state-of-the-art techniques significantly in terms of resource utilization in experimental evaluations using both benchmark and randomly generated task sets. We also present a method to deal with global EDF scheduling, which is a new technique proposed for response time analysis of sporadic DAG tasks with non-preemptive nodes.