Improving communication scheduling for array redistribution

Many scientific applications require array redistribution when the programs run on distributed memory parallel computers. It is essential to use efficient algorithms for redistribution, otherwise the performance of the programs will degrade considerably. The redistribution overheads consist of two parts: index computation and inter-processor communication. If there is no communication scheduling in a redistribution routine, the inter-processor communication will incur a larger communication idle time when there exists node contention and/or difference among message lengths during one particular communication step. In order to solve this problem, in this paper, we propose an efficient scheduling scheme that not only minimizes the number of communication steps and eliminates node contention, but also minimizes the difference of message lengths in each communication step. Thus, the communication idle time is reduced in redistribution routines.