Probabilistic rotation: scheduling graphs with uncertain execution time

Abstract

This paper proposes an algorithm called probabilistic rotation scheduling which takes advantage of loop pipelining to schedule tasks with uncertain times to a parallel processing system. These tasks normally occur when conditional instructions are employed and/or inputs of the tasks influence the computation time. We show that based on our loop scheduling algorithm the length of the resulting schedule can be guaranteed to be satisfied for a given probability. The experiments show that the resulting schedule length for a given probability of confidence can be significantly better than the schedules obtained by worst-case or average-case scenario.