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Subject: [OMPI users] Intra-node communication
From: Mudassar Majeed (mudassarm30_at_[hidden])
Date: 2012-06-01 10:34:07


Dear MPI people,                                Can someone tell me why MPI_Ssend takes more time when two MPI processes are on same node ...... ?? the same two processes on different nodes take much less time for the same message exchange. I am using a supercomputing center and this happens. I was writing an algorithm to reduce the across node communication. But now I found that across node communication is cheaper than communication within a node (with 8 cores on each node). best regards, Mudassar