A unified analysis of global EDF and fixed-task-priority schedulability of sporadic task systems on multiprocessors

Abstract

Fixed-task-priority (FTP) scheduling and earliest-deadline-first (EDF) scheduling policies are alike in fixing the priority of each job of a task at the time the job is released. This common feature of FTP and EDF scheduling permits a unified analysis of scheduling failures, to derive new sufficient tests for meeting all deadlines of a set of independent sporadic tasks under a global preemptive FTP or EDF scheduling policy. The performance of the new tests has been evaluated in comparison to prior schedulability tests, by simulation. The new tests are able to verify some schedulable task systems that could not be verified by prior tests, but also fail to verify some systems that can be verified by prior analysis techniques. The biggest gain appears to be for fixed-task-priority scheduling, especially with post-period deadlines.