Methods to Overlap Communication with Computation

In this work, Intel® MPI technology and its benchmark code/applications are used to obtain a better understanding of CCO. We apply non-blocking point-to-point exchange to mask the communication time needed with computation time. Intel® MPI is accompanied with an open source MPI Benchmark packages which include a non-blocking collective operation benchmark. The benchmark demonstrates the communication time versus computation time needed to produce certain percentage of overlap. We begin by modifying the Intel non-blocking collective operation benchmark to cater to the message sizes and operations used in an in-house parallel reservoir simulator. The findings serve as a guide in identifying CCO locations in our code and in maximizing the progression of communication achieving further overlap. In this paper, we share the benchmarks modification made for preliminary analysis of the MPI exchange behavior, the results of using asynchronous progression versus manual progression, the use of the results in deciding the overlapping changes made in our simulator code and the performance benefits of the modifications made.