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Tuning OpenMPI performance
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How to tune OpenMPi.
Non default settings on Stallo.
We have changed one setting on stallo to limit the memory consumption of the OpenMPI library. The following is set as global default:
btl_openib_free_list_max = 1000
This setting can be changed on the mpirun command-line:
mpirun --mca btl_openib_free_list_max 1000 ..........
or by setting it in the users personal config file, $HOME/.openmpi/mca-params.conf. See /opt/openmpi/1.2.4/etc/openmpi-mca-params.conf for the syntax.
The value of 1000 might be too low for some apps, you can try to set it to -1 to remove this limit if your application gets into problems. Please let us know if this influences your application.
