In this paper we present four new on-line algorithms for servicing soft aperiodic requests in real-time systems, where a set of hard periodic lash is scheduled using the Earliest Deadline First (EDF) algorithm. All the proposed solutions can achieve full processor ulilization and enhance aperiodic responsiveness, still guaranteeing the ezecution of the periodic tads. Operation of dhe algorithms, performance, schedulability analysis, and implemenlation compleaity are discussed and compared with classical alternative solutions, such as background and polling service. Ezlensive simulations show that algorithms with contained run-time overhead present nearly optimal responsiveness. A valuable contribdion of this work is to provide the real-dime system designer with a wide range of practical solu2ions which allow to balance eficiency against implementation complezity.
Marco Spuri, Giorgio C. Buttazzo