Complexity of task graph scheduling with fixed communication capacity

Theme 1 - Reseaux et systemes. Projet MISTRALSIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : 14802 E, issue : a.1996 n.2959 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Complexity of Task Graph Scheduling with Fixed Communication Capacity

Consider a scheduling problem of parallel computations in multiprocessor systems. Let a parallel program be modeled by a task graph, where vertices represent tasks and arcs the communications between tasks. An interprocessor communication time incurs when two tasks assigned to two different processors have to communicate. Such a scheduling problem has recently been studied in the literature, mostly for the case where interprocessor communication times are fully determined. In this paper, we consider the scheduling problem with communication resource constraints. More specically, we consider the case where all interprocessor communications take place on a network (communication medium) of bounded capacity. We consider two variants of the problem: communications with independent-data semantics or common-data semantics. We show that even for very specific subproblems, viz. scheduling of general graphs on two processors and scheduling of binary trees on infinite number of processors, the min..