Algorithms minimizing mean flow time: schedule-length properties

E. G. Coffman, Ravi Sethi

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)1-14
Number of pages14
JournalActa Informatica
Issue number1
StatePublished - Mar 1976

ASJC Scopus subject areas

  • Software
  • Information Systems
  • Computer Networks and Communications


Dive into the research topics of 'Algorithms minimizing mean flow time: schedule-length properties'. Together they form a unique fingerprint.

Cite this