On Fri, Dec 4, 2009 at 08:03, Ralph Castain <rhc@open-mpi.org> 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