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Acta Informatica

, Volume 6, Issue 1, pp 1–14 | Cite as

Algorithms minimizing mean flow time: schedule-length properties

  • E. G. CoffmanJr.
  • Ravi Sethi
Article

Summary

The mean flow time of a schedule provides a measure of the average time that a task spends within a computer system, and also the average number of unfinished tasks in the system. The mean flow time of a schedule is defined to be the sum of the finishing times of all tasks in the system. On a system of identical processors O(nlog n) algorithms exist for determining minimal mean flow time schedules for n independent tasks. In general, there will be a large class C of schedules, of widely differing lengths, that all minimize mean flow time. The problem of finding the shortest schedule in C is NP-complete. We give heuristics that find schedules in C that are no more than 25% longer than the shortest schedule in C. The advantage of a short schedule is that processor utilization is high.

Keywords

Information System Operating System Data Structure Communication Network Information Theory 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 1976

Authors and Affiliations

  • E. G. CoffmanJr.
    • 1
  • Ravi Sethi
    • 1
  1. 1.Computer Science Dept.The Pennsylvania State Univ.PennsylvaniaUSA

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