MPI Applications on Grids: A Topology Aware Approach

Porting on grids complex MPI applications involving collective communications requires significant program modification, usually dedicated to a single grid structure. The difficulty comes from the mismatch between programs organizations and grid structures: 1) large grids are hierarchical structures aggregating parallel machines through an interconnection network, decided at runtime and 2) the MPI standard does not currently provide any specific information for topology-aware applications, so almost all MPI applications have been developed following a non-hierarchical and non-flexible vision. In this paper, we propose a generic programming method and a modification of the MPI runtime environment to make MPI applications topology aware. In contrary to previous approaches, topology requirements for the application are given to the grid scheduling system. which exposes the compatible allocated topology to the application.