Tuning Utility Output

Upon completion of the tuning process, the IntelĀ® MPI Library tuning utility records the chosen values in the configuration file in the following format:

 -genv I_MPI_DYNAMIC_CONNECTION 1
-genv I_MPI_ADJUST_REDUCE 1:0-8

The Intel MPI Library tuning utility ignores any environment variables that have no effect on the application when the difference between probes is at the noise level (1%). In this case, the utility does not set the environment variable and preserves the default library heuristics.

In the case of an tuning application that has significant run-to-run performance variation, the Intel MPI Library tuning utility might select divergent values for the same environment variable under the same conditions. To improve decision accuracy, increase the number of iterations for each test run with the --iterations command line option. The default value for the number of iterations is 3.