Monoprocessor Real-Time Scheduling of Data Dependent Tasks with Exact Preemption Cost for Embedded Systems

Abstract—Most safety critical embedded systems, i.e. systems for which constraints must necessarily be satisfied in order to avoid catastrophic consequences, consist of a set of data depen-dent tasks which exchange data. Although non-preemptive real-time scheduling is safer than preemptive real-time scheduling in a safety critical context, preemptive real-time scheduling provides a better success ratio, but the preemption has a cost. In this paper we propose a schedulability analysis for data dependent periodic tasks which takes into account the exact preemption cost, data dependence constraints without loss of data and mutual exclusion constraints. Keywords-real-time scheduling, exact preemption cost, data dependent tasks, data transfer, mutual exclusion constraints, schedulability analysis, safety critical embedded systems. I