Improving MPI Applications Performance on Multicore Clusters with Rank Reordering

Guillaume Mercier (1, 2) , Emmanuel Jeannot (1)

1 RUNTIME - Efficient runtime systems for parallel architectures
2 LaBRI - Laboratoire Bordelais de Recherche en Informatique

Modern hardware architectures featuring multicores and a complex memory hierarchy raise challenges that need to be addressed by parallel applications programmers. It is therefore tempting to adapt an application communication pattern to the characteristics of the underlying hardware. The MPI standard features several functions that allow the ranks of MPI processes to be reordered according to a graph attached to a newly created communicator. In this paper, we explain how the MPICH2 implementation of the MPI_Dist_graph_create function was modified to reorder the MPI process ranks to create a match between the application communication pattern and the hardware topology. The experimental results on a multicore cluster show that improvements can be achieved as long as the application communication pattern is expressed by a relevant metric.

Mots clés: Message-Passing; multicore architectures; process placement; rank reordering; communication pattern

Domaines: Calcul parallèle, distribué et partagé [cs.DC]

Guillaume Mercier, Emmanuel Jeannot. Improving MPI Applications Performance on Multicore Clusters with Rank Reordering. EuroMPI, Sep 2011, Santorini, Italy. pp.39-49, ⟨10.1007/978-3-642-24449-0⟩. ⟨hal-00643151⟩