Heuristic algorithms for task assignment and scheduling in a processor network

Abstract

This paper addresses the problem of statically assigning and scheduling parallel executable tasks to processor networks in parallel or distributed computers to meet real-time computing constraints. Three procedures are carried out for the task assignment and scheduling. First, a task assignment algorithm is used to group M tasks into N task clusters and then initially to assign the N clusters onto N processors without considering the communication link constraints of the processors. Then a communication link number reduction algorithm is applied to remove the excess number of links according to the design limitations of the processors. A new structure of the processor network suitable for the N task clusters is then determined. Finally, the N assigned task clusters are scheduled by a task scheduling algorithm in order to minimize the idle time caused by interprocessor synchronized data communication and indirect data communication. The proposed algorithms are based on the family of heuristic approaches, and are particularly suitable for large grain parallel tasks and message passing parallel computers.