Comparison and tuning of MPI implementations in a grid context

Ludovic Hablot, Olivier Glück, Jean-Christophe Mignot, Stéphane Genaud et Pascale Vicat-Blanc Primet

Keywords: MPI evaluation, Grid'5000, NPB, TCP, ray2mesh.

Overview:

Today, clusters are often interconnected by long distance networks within grids to offer a huge number of available ressources to a range of users. MPI, the standard communication library used to write parallel applications, has been implemented for clusters. Two main features of grids: long distance networks and technological heterogeneity, raise the question of MPI efficiency in grids. This work evaluate four recent MPI implementations (MPICH2, MPICH-Madeleine, OpenMPI and GridMPI) in the french research grid: Grid'5000. The comparison is based on the execution of pingpong, NAS Parallel Benchmarks and a real application in geophysics (ray2mesh). We show that this implementations present performance differences. Executing MPI applications on the grid can be beneficial if the parameters are well tuned. Collective operations have to be improved to be efficient.

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