Deadline Assignment to Reduce Output Jitter of Real-time Tasks

In real-time control system, output jitter of a task is important when feedback control loops are implemented as execution of periodic tasks. Output jitter refers to the variation of response time of a periodic task. For the stability of the control system, output jitter should be reduced. This paper aims to reduce the output jitter of real-time tasks under EDF scheduling. The proposed scheme derives a linear program from execution times and periods of given tasks. To this end, this paper devises an objective function of linear program which reduces the output jitter and derives the constraints of linear program from the schedulability condition of EDF scheduling. The simulation measures the maximum and mean output jitter and relative output jitter to evaluate the performance of the proposed scheme. The simulation results show that the output jitter is reduced by 4-12% on average.