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Subject: [OMPI users] Open MPI vs IBM MPI performance help
From: Price, Brian M (N-KCI) (brian.m.price_at_[hidden])
Date: 2010-12-01 13:29:12

OpenMPI version: 1.4.3
Platform: IBM P5, 32 processors, 256 GB memory, Symmetric Multi-Threading (SMT) enabled
Application: starts up 48 processes and does MPI using MPI_Barrier, MPI_Get, MPI_Put (lots of transfers, large amounts of data)
Issue: When implemented using Open MPI vs. IBM's MPI ('poe' from HPC Toolkit), the application runs 3-5 times slower.
I suspect that IBM's MPI implementation must take advantage of some knowledge that it has about data transfers that Open MPI is not taking advantage of.
Any suggestions?
Brian Price