Measuring Pure Communication Time

To measure pure execution time of nonblocking collective operations, use the _pure flavor of the IMB-NBC benchmarks. The benchmark methodology is consistent with the one used for regular collective operations:

These benchmarks are not included into the default list of IMB-NBC benchmarks. To run a benchmark, specify the particular benchmark name or use the –include command-line parameter. For example:

$ mpirun -np 2 IMB-NBC Ialltoall_pure
$ mpirun -np 2 IMB-NBC -include Iallgather_pure Ialltoall_pure

Displaying Results

Pure nonblocking collective benchmarks show bare timing values. Since execution time may vary for different ranks, three timing values are shown: maximum, minimum, and the average time among all the ranks participating in the benchmark measurements.  

See Also

IMB-NBC Benchmarks
Measuring Communication and Computation Overlap
Command-Line Control