[Beowulf] MPICH question
lusk at mcs.anl.gov
Tue Feb 22 21:12:17 PST 2005
From: John Lau <cflau at clustertech.com>
Subject: [Beowulf] MPICH question
Date: Tue, 22 Feb 2005 09:30:29 +0800
> I have a question on the number of processes spawned by MPICH. I am
> using MPICH 220.127.116.11 --with-device=ch_p4. When I use mpirun -np 4 to
> start a mpi process, total 8 processes will be spawned. But only 4
> processes have loadings on CPUs. I would like to know if it is the
> correct behavior of MPICH? And what's the use of the 4 no-loading
> process? Thank you.
The other 4 processes are "listener" processes that permit dynamic
creation of connections as they are needed. What you see is the correct
behavior. We recommend that MPICH1 users switch to MPICH2.
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