Improved Response-Time Analysis Calculations

Schedulability analysis of fixed priority preemptive scheduled systems can be performed by calculating the worst-case response-time of the involved processes. The system is deemed schedulable if the calculated responsetime for each process is less than its corresponding deadline. It is desirable that the Response-Time Analysis (RTA) can be efficiently performed. This is particularly important in dynamic real-time systems when a fast response is needed to decide whether a new job can be accommodated, or when the RTA is extensively applied, e.g., when used to guide the heuristics in a higher level optimiser. This paper presents a set of methods to improve the efficiency of RTA calculations. The methods are proved correct, in the sense that they give the same results as traditional (non-improved) RTA. We also present an evaluation of the improvements, by applying them to the particularly time-consuming traffic model used in RTA for ATM communication networks. Our evaluation shows that the proposed methods can give an order of magnitude reduction of the execution time of RTA. Copyright 1998 IEEE. Published in the Proceedings of Rtss’98, 1 December 1998 in Madrid, Spain. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works, must be obtained from the IEEE. Contact: Manager, Copyrights and Permissions / IEEE Service Center / 445 Hoes Lane / P.O. Box 1331 / Piscataway, NJ 08855-1331, USA. Telephone: + Intl. 732-562-3966.