Intel® MPI Library Reference Manual for Linux* OS
To find the optimal settings for tuning your cluster, run the mpitune utility once after the Intel® MPI Library installation and after every cluster configuration change (processor or memory upgrade, network re-configuration, and so on.). To get the list of settings, run the utility under the user account that was used for the Intel® MPI Library installation, or appropriately set the tuner data directory through the --output-directory option and the results directory through the --output-directory-results option.
If there are any configuration files in the <installdir>/<arch>/etc directory, the recorded Intel® MPI Library configuration settings are used automatically by mpirun with the -tune option.
For example:
Collect configuration settings for the cluster hosts listed in the ./mpd.hosts file by using the Intel® MPI Benchmarks
$ mpitune
Use the optimal recorded values when running on the cluster
$ mpirun -tune -n 32 ./myprog
The job launcher finds a proper set of configuration options based on the following execution conditions: communication fabrics, number of hosts and processes, etc. If you have write access permission for <installdir>/<arch>/etc, all generated files are saved in this directory; otherwise the current working directory is used.
When you use the -tune option in the cluster specific mode (such as, without the tuning configuration file name), you need to explicitly select the communication device or fabric, the number of processes per node, and the total number of processes. For example:
$ mpirun -tune -genv I_MPI_FABRICS shm:dapl -ppn 8 -n 32 ./myprog