Non-uniform Dependence Loops

Abstract

In general, synchronization mechanism can be used to preserve dependence constraints of any nested loops, and it can be combined with loop scheduling scheme to form a uniform framework. Meanwhile, correct execution order and balance workload distribution will be achieved. In this paper, we propose a new scheduling scheme called M-hopping method to schedule non-uniform dependence doubly nested loop on multiprocessor systems. To initialize a set of hopping information, our approach is based on the concept of minimum dependence distance. During runtime, hopping information will be used to adjust number of parallelizable iterations. According to our experimental results, if loops carry sufficient parallelism, our proposed method will reliably exploit parallelism, and outperform most of the existing non-uniform dependence loop scheduling schemes by 20.29 in average.