Improving the Efficiency of Schedulability Tests for Fixed Priority Preemptive Systems

Efficient schedulability tests are required to check the schedulability of real-time systems, especially for online use. Since exact tests are very time consuming, great efforts have been paid to search for more efficient tests. Sufficient tests have been widely studied for they are usually performance efficiency. If a task set is proved schedulable by the sufficient test, then the exact response time does not need to be calculated. In this paper, we discuss the way of how to find better initial values for sufficient schedulability tests. Four parametric initial values are proposed and each can be tuned using a delta-parameter to reduce the number of iterations needed by response time calculation. Extensive evaluations show that the schedulability tests found by our method need less runtime than state of the art approaches.