Using application communication characteristics to drive dynamic MPI reconfiguration

Modern HPC applications, for example adaptive mesh refinement and multi-physics codes, have dynamic communication characteristics which result in poor performance on current MPI implementations. Current MPI implementations do not change transport protocols or allocate resources based on the application characteristics, resulting in degraded application performance. In this paper, we describe PRO-MPI, a protocol reconfiguration and optimization system for MPI that we are developing to meet the needs of dynamic modern HPC applications. PRO-MPI uses profiles of past application communication characteristics to dynamically reconfigure MPI protocol choices. We show that such dynamic reconfiguration can improve the performance of important MPI applications significantly when exact communication profiles are known. We also present preliminary data showing that profiles from past application runs with different (but related) inputs can be used to optimize the performance of later application runs.