Optimizing PARSEC for Knights Landing

Abstract

PARSEC is a massively parallel Density-Functional-Theory (DFT) code. Within the modernization effort towards the new Intel Knights Landing platform, we adapted the main computational kernel, represented as high-order finite-difference stencils, to use hybrid MPI and OpenMP* runtimes. We also employed MPI-3 non-blocking neighborhood collectives for the halo exchange. We present performance data on the Knights Landing platform including MPI traces portraying our exploration of communication-computation overlap in a hybrid MPI and OpenMP application, and the fine-tuning of the interplay between the load-balancing - static at the MPI level and dynamic in OpenMP.