Aggressive online deadline scheduling

Abstract

This paper is concerned with online algorithms for scheduling jobs with deadlines on a single processor. It has been known for long that unless the system is underloaded, no online scheduling algorithm can be 1-competitive, i.e., matching the performance of the optimal offline algorithm. Nevertheless, recent work has revealed that some online algorithms using a moderately faster processor (or extra processors) can significantly improve the competitiveness [J. ACM 47 (2000) 617] or even be 1-competitive [Proc. SODA (2001) 755, Proc. SPAA (2002) 133]. This paper takes a further step to investigate online scheduling algorithms with an even higher performance guarantee (i.e., better than 1-competitive algorithms) and in particular, presents an extra-resource analysis of the earliest-deadline-first strategy (EDF) with respect to such a higher performance guarantee. © 2004 Published by Elsevier B.V.