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Summary: Improved Conditions for Bounded Tardiness under EPDF Fair
Multiprocessor Scheduling
UmaMaheswari C. Devi and James H. Anderson
Department of Computer Science, The University of North Carolina, Chapel Hill, NC
Abstract
The earliest-pseudo-deadline-first (EPDF) Pfair al-
gorithm is more efficient than other known Pfair
scheduling algorithms, but is not optimal on more than
two processors. In earlier work, Srinivasan and Ander-
son established a sufficient per-task utilization restric-
tion for ensuring a tardiness of at most one quantum
under EPDF. They also conjectured that a tardiness
bound of one quantum applies to systems that are not
restricted in any way. In this paper, we present coun-
terexamples that show that this conjecture is false. We
also present sufficient utilization restrictions that are
more liberal than theirs.
Keywords: soft real-time systems, pfairness, real-time
scheduling, multiprocessors, tardiness bounds.
1 Introduction
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