Schedulability Analysis of Fixed Priority Systems with Scheduling Overheads

Abstract

In this paper, the author extends the traditional exact schedulability analysis for fixed priority (FP) preemptive scheduling by taking into account the extra scheduling overhead that may be induced by context switching. Then the author develops a necessary and sufficient scehdulability test for fixed priority scheduling on a single processor by considering the worst-case task response time. In the paper, the existing results on exact response time analysis have been discussed for fixed priority preemption schecduling with task set that is periodic or sporadic periodic respectively. As a generalization of fixed priority preemptive scheduling, the fixed priority preemption-threshold scheduling is also described in this paper. An improvement upon the previous results has been proposed by considering the influence of task response time caused by the context switching overhead and release jitter. Accounting for context switching overhead needs to increase the execution time of each task. The author also extends this analysis to consider the task response time with arbitrary deadlines.