Semi-Fixed-Priority Scheduling: New Priority Assignment Policy for Practical Imprecise Computation

Abstract

This paper proposes semi-fixed-priority scheduling to achieve both low-jitter and high schedulability. Semi-fixed-priority scheduling is for the extended imprecise computation model, which has a wind-up part as a second mandatory part and schedules the part of each extended imprecise task with fixed-priority. This paper also proposes a novel semi-fixed-priority scheduling algorithm based on Rate Monotonic (RM), called Rate Monotonic with Wind-up Part (RMWP). RMWP limits executable ranges of wind-up parts to minimize jitter. The schedulability analysis proves that one task set is feasible by RMWP if the task set is feasible by RM. Simulation results show that RMWP has both lower jitter and higher schedulability than RM.