Real-Time Scheduling for Reducing Jitters of Periodic Tasks

Abstract

For control applications implemented with periodic tasks, fluctuations in start or response timing cause jitters which may disturb periodicity and result in performance degradation or instability. This study proposes real-time scheduling techniques that reduce jitters and average response times of periodic tasks. In the proposed scheduling, two techniques are employed: one which adaptively extends deadlines according to varying execution times, and the other which further obtains short deadlines by virtually advancing release times. These two techniques aim at scheduling target tasks as early as possible by giving them short enough deadlines. The evaluation shows that the former shortens average response times of the target tasks by up to 20.5% and the latter mitigates jitters by up to 35.4%, compared to the existing scheduling algorithm, Total Bandwidth Server.