Minimizing mean flow-time with parallel processors and resource constraints

Abstract

The problem to be considered is one of scheduling nonpreemptable tasks in multiprocessor systems when tasks need for their processing processors and other limited resources, and when mean flow time is the system performance measure. For each task the time required for its processing and the amount of each resource which it requires, are given. Special attention is paid to the computational complexity of algorithms for determining the optimal schedules for different assumptions concerning the environment. For the case of scheduling independent, arbitrary length tasks when each task may require a unit of an additional resource of one type, an O(n 3) algorithm is given. For more complicated resource requirements, however, it is proved that the problem under consideration is NP-hard in the strong sense, even for the case of two processors.