hwloc: a Generic Framework for Managing Hardware Affinities in HPC Applications

François Broquedis 1, 2 Jérôme Clet-Ortega 1, 2 Stéphanie Moreaud 1, 2 Nathalie Furmento 1, 2 Brice Goglin 1, 2 Guillaume Mercier 1, 2 Samuel Thibault 1, 2 Raymond Namyst 1, 2
2 RUNTIME - Efficient runtime systems for parallel architectures
Inria Bordeaux - Sud-Ouest, UB - Université de Bordeaux, CNRS - Centre National de la Recherche Scientifique : UMR5800
Abstract : The increasing numbers of cores, shared caches and memory nodes within machines introduces a complex hardware topology. High-performance computing applications now have to carefully adapt their placement and behavior according to the underlying hierarchy of hardware resources and their software affinities. We introduce the Hardware Locality (hwloc) software which gathers hardware information about processors, caches, memory nodes and more, and exposes it to applications and runtime systems in a abstracted and portable hierarchical manner. hwloc may significantly help performance by having runtime systems place their tasks or adapt their communication strategies depending on hardware affinities. We show that hwloc can already be used by popular high-performance OpenMP or MPI software. Indeed, scheduling OpenMP threads according to their affinities or placing MPI processes according to their communication patterns shows interesting performance improvement thanks to hwloc. An optimized MPI communication strategy may also be dynamically chosen according to the location of the communicating processes in the machine and its hardware characteristics.
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Submitted on : Wednesday, November 4, 2009 - 8:07:08 PM
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François Broquedis, Jérôme Clet-Ortega, Stéphanie Moreaud, Nathalie Furmento, Brice Goglin, et al.. hwloc: a Generic Framework for Managing Hardware Affinities in HPC Applications. PDP 2010 - The 18th Euromicro International Conference on Parallel, Distributed and Network-Based Computing, Feb 2010, Pisa, Italy. ⟨10.1109/PDP.2010.67⟩. ⟨inria-00429889⟩



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