Performance Profiling Overhead Compensation for MPI Programs

Abstract. Performance profiling of MPI programs generates overhead during execution that introduces error in profile measurements. It is possible to track and remove overhead online, but it is necessary to communicate execution delay between processes to correctly adjust their interdependent timing. We demonstrate the first implementation of a onlne measurement overhead compensation system for profiling MPI programs. This is implemented in the TAU performance systems. It requires novel techniques for delay communication in the use of MPI. The ability to reduce measurement error is demonstrated for problematic test cases and real applications