MPInside: a performance analysis and diagnostic tool for MPI applications.

ABSTRACTPerformance analysis and prediction of parallel applications using the Message-Passing Interface (MPI) standard is a challenging task. Collecting, organizing, and making sense of profiling data for MPI jobs of even modest scale is difficult and time-consuming. The task is further complicated by the inherent difficulty in interpreting the resulting communication measurements. In this paper we introduce MPInside, a new profiling and diagnostic tool that overcomes these constraints with carefully considered choices for measurement techniques, capabilities, and output formats. Using examples from real-world applications, we illustrate the innovative features of the tool--including late senders for point-to-point calls and unaligned collective calls--all in an instrumentation-free framework. We also demonstrate the in-flight modeling capabilities of MPInside with several "what if" experiments.