Minimizing mean flow time with error constraint

Joseph Y.T. Leung, Tommy W. Tam, C. S. Wong, Gilbert H. Young

Research output: Chapter in Book/Report/Conference proceedingConference contribution

10 Scopus citations


In a new model of task systems studied by J. W. S. Liu et al. (ibid., pp. 252-260, 1987) each task is logically decomposed into two subtasks, mandatory and optional. The authors discuss preemptively scheduling this kind of task system on p ≥ 1 identical processors so as to minimize the mean flow time. Given a task system and an error threshold K, the goal is to find a preemptive schedule such that each task is executed in the interval of its release time and deadline, the average error is no more than K, and the mean flow time of the schedule is minimized. Such a schedule is called an optimal schedule. It is shown that the problem of finding an optimal schedule is NP-hard for each p ≥ 1, even if all tasks have the same ready time and deadline. For a single processor, a pseudo-polynomial time algorithm and polynomial time algorithms for various special cases of the problem are given.

Original languageEnglish (US)
Title of host publicationProceedings - Real-Time Systems Symposium
Editors Anon
PublisherPubl by IEEE
Number of pages10
ISBN (Print)0818620048
StatePublished - 1989
Externally publishedYes
EventProceedings - Real-Time Systems Symposium - Santa Monica, CA, USA
Duration: Dec 5 1989Dec 7 1989

Publication series

NameProceedings - Real-Time Systems Symposium


OtherProceedings - Real-Time Systems Symposium
CitySanta Monica, CA, USA

All Science Journal Classification (ASJC) codes

  • Software
  • Hardware and Architecture
  • Computer Networks and Communications


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