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Subject: Re: [OMPI users] MPI_Comm_spawn, caller uses CPU while waiting for spawned processes
From: Nicolas Bock (nicolasbock_at_[hidden])
Date: 2009-12-04 10:13:20


On Fri, Dec 4, 2009 at 08:03, Ralph Castain <rhc_at_[hidden]> wrote:

>
>
> It is polling at the barrier. This is done aggressively by default for
> performance. You can tell it to be less aggressive if you want via the
> yield_when_idle mca param.
>
>
How do I use this parameter correctly? I tried

/usr/local/openmpi-1.3.4-gcc-4.4.2/bin/mpirun -np 3 --mca
mpi_yield_when_idle 1 ./master

but still get

nbock 20794 0.0 0.0 53980 2344 pts/2 S+ 08:11 0:00
/usr/local/openmpi-1.3.4-gcc-4.4.2/bin/mpirun -np 3 --mca
mpi_yield_when_idle 1 ./master
nbock 20795 96.7 0.0 159096 3896 pts/2 R+ 08:11 1:10 ./master
nbock 20796 0.0 0.0 158960 3804 pts/2 S+ 08:11 0:00 ./master
nbock 20797 0.0 0.0 158960 3804 pts/2 S+ 08:11 0:00 ./master
nbock 20813 88.1 0.0 158964 3892 pts/2 R+ 08:12 0:08 ./slave
arg1 arg2
nbock 20814 86.9 0.0 158964 3908 pts/2 R+ 08:12 0:08 ./slave
arg1 arg2
nbock 20815 87.5 0.0 158964 3900 pts/2 R+ 08:12 0:08 ./slave
arg1 arg2

nick