An Integrated Scheduling Algorithm for Precedence Constrained Hard and Soft Real-Time Tasks on Heterogeneous Multiprocessors

Abstract

In this paper, we propose a duplication-based algorithm (IDSA) for the integrated scheduling of precedence related real-time tasks with hard and soft deadlines on a set of heterogeneous multiprocessors. We employ a priority-based scheme in which the hard subtasks are always allotted a higher priority as compared to the soft subtasks. IDSA utilizes selective subtask duplication that enables some subtasks to have earlier start times, which results in an increased number of subtasks (and hence task sets) finishing before their deadlines, thereby increasing the schedulability of a real-time application. Our algorithm is also shown to be capable of scheduling a real-time application even if the available number of processors is less than the required number of processors. Based on extensive simulation results, we observe that IDSA offers better success ratio as compared to the existing algorithms in the literature when communication is a dominant factor in the system.