A Comparison of MPI and Hybrid MPI+OpenMP Programming Paradigms Using Multi-Core Processors

Abstract A decade ago CPUs speed could not be increased without extra ordinary cooling and consequently hit a clock speed barrier. Processors design then was switched to multi-core architecture that minimizes energy consumption. The multicore architecture is introduced to improve computing performance by providing hardware parallelism through more CPU cores, each having restrained clock speed. This has been a break through in High Performance Computing (HPC). While more processor cores rendered effective execution results, multi-core technology inaugurated an extra layer of complexity for programming issues. To exploit each core in a multi-core environment, application software should be optimized by using multithreading. Multi-core processors can even degrade the performance for single threaded application due to reduction in clock speed. In this paper we compare performance of multithreading finegrained and course-grained computational problems further flavored as computation-intensive and data-intensive problems by using MPI and hybrid MPI+OpenMP approach.