Conference · 2002
Feedback Control theory for Real-time Scheduling
D. Sahoo, M. V. Salapaka, Al-Omari, R. Somani A. Manimaran, G.
American Control Conference, col.2
Abstract
Most real-time scheduling algorithms are open-loop algorithms as the scheduling decisions are based on the worst-case estimates of task parameters. In recent years, the "closed - loop" scheduling has gained importance due to its applicability to many real-world problems wherein the feedback information can be exploited efficiently to adjust task and/or scheduler parameters, thereby improving the system's performance. In this paper, we discuss an open-loop dynamic scheduling algorithm that employs a notion of task overlap in the scheduler in order to provide some flexibility in task execution time. Then we present a novel closed-loop approach for dynamically estimating the execution time of tasks based on both deadline miss ratio and task rejection ratio in the system. This approach is highly preferable for firm/soft real-time systems since it provides a firm performance guarantee in terms of deadline misses while achieving a high guarantee ratio. We design the proportional-integral controller and H infin; controller for closed loop scheduling. We evaluate the performance of the open-loop and the closed-loop approaches using simulation studies. We show that the closed-loop dynamic scheduling offers a better performance over the open-loop scheduling under all practical conditions.
BibTeX
@inproceedings{sahoo-2002-feedback-control-theory-for-real-time-scheduling,
title = {Feedback Control theory for Real-time Scheduling},
author = {D. Sahoo and M. V. Salapaka and Al-Omari and R. Somani A. Manimaran and G.},
booktitle = {American Control Conference, col.2},
year = {2002}
}