Survey on Optimal Schedulability Test for Hard Real Time Scheduling

Abstract: Real time system is now ubiquitous. In such real time system requires the exactness in result of logical behavior and physical occurrence at which the results are produced. Throughout the paper we consider only hard real time tasks implement on uniprocessor and if dead line is missed in such system then its ruinous. Many scheduler had been proposed to improve the schedulability, here we talks about dynamic and static scheduling only like Earliest Deadline First (EDF) and Rate Monotonic (RM) and considering a scenario of only D  T. We analyze tasks in every condition to check its schedulability with respected solution to each problem. First we check utilization of tasks to verify its schedulability, but for optimal schedulability we required response time analysis. Again during task interaction some issues occur such as blocking, priority inversion and jitter which also need to verify. That all issues where discuss and analyze throughout the paper with the help of examples with their solutions.

Keywords: Real time system, task scheduling, EDF, RM, utilization, response time analysis, priority inversion, jitter.