Efficient Scheduling of Tasks without Full Use of Processor Resources

Abstract The nonpreemptive scheduling of a partially ordered set of tasks on a machine with m processors of different speeds is studied. Polynomial time algorithms are presented which benefit from selective non-use of slow processors. The performance of these heuristics is asymptotic to √ m times worse than optimal, whereas list schedules are unboundedly worse than optimal for any fixed value of m . The techniques of analyzing these schedules are used to obtain a bound on a large class of preemptive schedules.