Selectively Enabling Probes

One might focus data collection on events that are believed to be most relevant to performance in order either to reduce sizes of buffer files or to make profiling less intrusive. TNF probes are organized in probe groups. For the TNF-instrumented version of the Sun MPI library, the probe groups are structured as follows:

Figure 7-12 Sun MPI TNF Probe Groups

Some TNF probes belong to more than one group in the TNF-instrumented version of the Sun MPI library. For example, there are several probes that belong to both the mpi_request group and the mpi_pt2pt group. For further information about probe groups, see the Sun MPI 4.0 Programming and Reference Guide.

For message-passing performance, typically the most important groups are

• mpi_pt2pt - point-to-point message passing

• mpi_request - other probes for asynchronous point-to-point calls

• mpi_coll - collectives

• mpi_io_rw - file I/O

If there is heavy use of MPI_Pack and MPI_Unpack, their probes should also be enabled.