Comparison and tuning of MPI implementations in a grid context

Today, clusters are often interconnected by long distance networks to compose grids and to provide users with a huge number of available ressources. To write parallel applications, developers are generally using the standard communication library MPI, which has been optimized for clusters. However, two main features of grids - long distance networks and technological heterogeneity - raise the question of MPI efficiency in grids. This paper presents an evaluation and tuning of four recent MPI implementations (MPICH2, MPICH-Madeleine, OpenMPI and YAMPII) in a research grid: Grid’5000. The comparison is based on the execution of pingpong and NAS Parallel Benchmarks. We show that these implementations present several performance differences. We show that YAMPII performs better results than the others. But we argue that executing MPI applications on a grid can be beneficial if some specific parameters are well tuned. The paper details, for each implementation, the tuning leading the best performances.