A recursive algorithm for scheduling of tasks in a heterogeneous distributed environment

Optimal scheduling of parallel tasks with some precedence is critical for achieving high performance in heterogeneous computing system. The application scheduling is known to be NP-complete in general cases. The complexity of the problem increase when task scheduling is to be done in a heterogeneous environment. This paper presents a recursive task scheduling algorithm for a bounded number of heterogeneous processors run on the network of Heterogeneous systems. It is three-phase task scheduling algorithm. The task-prioritizing phase is to is to compute the upward rank of each task and assign the priority to all tasks. The processor selection phase is to schedule the tasks onto the processors that give the latest start time for the task. The moving phase is to move all the possible tasks until the starting time of the entry task is zero. The performance of the algorithm is illustrated by comparing the scheduling length ratio, frequency of best results with the existing effectively scheduling algorithms, Heterogeneous Earliest Finish Time and Iterative List Scheduling algorithm.