Balancing Load versus Decreasing Communication: Parameterizing the Tradeoff

Abstract

Domain decomposition is an important step for parallel scientific applications, in particular finite element analyses. A good decomposition will minimize both the time spent on local computation and on interprocessor communication. It is often the case that these two goals cannot be satisfied simultaneously. In this paper, we use analytical and experimental results to illustrate the importance of considering the target architecture as well as the application when determining which factor to emphasize in a decomposition method. In particular, we derive a parameter j 0 that provides some guidelines as to which goal should be given primary focus. Our results yield two interesting facts: (1) allowing some load imbalance can provide some reduction in communication and total execution time and (2) as larger numbers of processors are applied to a problem, larger amounts of load imbalance are beneficial. Corresponding author: Eric J. Schwabe Department of ECE Northwestern University 2145 She..