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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 earliestpseudodeadlinefirst (EPDF ) Pfair al
gorithm is more e#cient than other known Pfair
scheduling algorithms, but is not optimal on more than
two processors. In earlier work, Srinivasan and Ander
son established a su#cient pertask 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 su#cient utilization restrictions that are
more liberal than theirs.
Keywords: soft realtime systems, pfairness, realtime
scheduling, multiprocessors, tardiness bounds.
1 Introduction
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