Title: Atmospheric models hybrid OpenMP/MPI implementation multicore cluster evaluation

Authors: Carla Osthoff; Francieli Zanon Boito; Rodrigo Virote Kassick; Laércio Lima Pilla; Philippe O.A. Navaux; Claudio Schepke; Jairo Panetta; Pablo Javier Grunmann; Nicolas Maillard; Pedro L. Silva Dias; Robert L. Walko

Addresses: Laboratório Nacional de Computação Científica (LNCC), Av. Getúlio Vargas, 333, Quitandinha, Petrópolis – Rio de Janeiro, CEP: 25651-075, Brazil. ' Instituto de Informática – Universidade Federal do Rio Grande do Sul (UFRGS), Av. Paulo Gama, 110 – Bairro Farroupilha – Porto Alegre – Rio Grande do Sul, CEP: 90040-060, Brazil. ' Instituto de Informática – Universidade Federal do Rio Grande do Sul (UFRGS), Av. Paulo Gama, 110 – Bairro Farroupilha – Porto Alegre – Rio Grande do Sul, CEP: 90040-060, Brazil. ' Instituto de Informática – Universidade Federal do Rio Grande do Sul (UFRGS), Av. Paulo Gama, 110 – Bairro Farroupilha – Porto Alegre – Rio Grande do Sul, CEP: 90040-060, Brazil. ' Instituto de Informática – Universidade Federal do Rio Grande do Sul (UFRGS), Av. Paulo Gama, 110 – Bairro Farroupilha – Porto Alegre – Rio Grande do Sul, CEP: 90040-060, Brazil. ' Instituto de Informática – Universidade Federal do Rio Grande do Sul (UFRGS), Av. Paulo Gama, 110 – Bairro Farroupilha – Porto Alegre – Rio Grande do Sul, CEP: 90040-060, Brazil. ' Instituto Nacional de Pesquisas Espaciais (INPE), Rodovia Presidente Dutra, Km 40, SP-RJ 12630-000, Cachoeira Paulista, Brazil. ' Laboratório Nacional de Computação Científica (LNCC), Av. Getúlio Vargas, 333, Quitandinha, Petrópolis – Rio de Janeiro, CEP: 25651-075, Brazil. ' Instituto de Informática – Universidade Federal do Rio Grande do Sul (UFRGS), Av. Paulo Gama, 110 – Bairro Farroupilha – Porto Alegre – Rio Grande do Sul, CEP: 90040-060, Brazil. ' Laboratório Nacional de Computação Científica (LNCC), Av. Getúlio Vargas, 333, Quitandinha, Petrópolis – Rio de Janeiro, CEP: 25651-075, Brazil. ' Rosenstiel School of Marine and Atmospheric Science University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149-1098, USA

Abstract: Atmospheric models usually demand high processing power and generate large amounts of data. As the degree of parallelism grows, the I/O operations may become the major impacting factor of their performance. This work shows that a hybrid MPI/OpenMP implementation can improve the performance of the atmospheric model ocean-land-atmosphere model (OLAM) on a multicore cluster environment. We show that the hybrid MPI/OpenMP version of OLAM decreases the number of output files, resulting in better performance for I/O operations. We have evaluated OLAM on the parallel file system PVFS and shown that storing the files on PVFS results in lower performance than using the local disks of the cluster nodes due as a consequence of file creation and network concurrency. We have also shown that further parallel optimisations should be included in the hybrid version in order to improve the parallel execution time of OLAM.

Keywords: OpenMP; MPI; hybrid implementation; multicore clusters; performance evaluation; atmospheric modelling; cluster evaluation; OLAM; parallel execution time.

DOI: 10.1504/IJITCC.2012.050411

International Journal of Information Technology, Communications and Convergence, 2012 Vol.2 No.3, pp.212 - 233

Published online: 16 Aug 2014 *

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