An EDF schedulability test for periodic tasks on reconfigurable hardware devices

Abstract

In this paper, we consider the scheduling of periodic real-time tasks on reconfigurable hardware devices. Such devices can execute several tasks in parallel. All executing tasks share the hardware resource, which makes the scheduling problem differ from single- and multiprocessor scheduling. We adapt the global EDF multiprocessor scheduling approach to the reconfigurable hardware execution model and define two preemptive scheduling algorithms, EDF-First-k-Fit and EDF-Next-Fit . For these algorithms, we present a novel linear-time schedulability test and give a proof based on a resource augmentation technique. Then, we propose a task placement and relocation scheme utilizing partial device reconfiguration. This scheme allows us to extend the schedulability test to include reconfiguration time overheads. Experiments with synthetic workloads compare the scheduling test with the actual scheduling performance of EDF-First-k-Fit and EDF-Next-Fit . The main evaluation result is that the reconfiguration overhead is acceptable if the task computation times are one order of magnitude higher than the device reconfiguration time.