Simulation based performance prediction by PEPSY

Parallel programs, generated by the supercompiler, VFCS (Vienna Fortran Compilation System), are an application area for the tool, PEPSY (PErformance Prediction SYstem), which we have developed recently. PEPSY derives a performance model from an internal representation of the parallel program in the compiler, automatically, and makes performance analysis by discrete-event simulation. Several monitoring modes of PEPSY enable to analyze a parallel program behavior at the detailed and global level, evaluating static and dynamic performance indices. Performance prediction is carried out before the final target parallel code is generated, or before a real run is executed on the parallel computer, in order to optimize the parallelization strategy for VPCS. This paper is focused on the prediction of a new subset of performance indices for the parallel programs, evaluated by PEPSY, and illustrating its new monitoring facilities suitable for comparison of different versions of the program