PRISM_TNFDIR

Prism uses space in a target directory (by default, /usr/tmp) to store the temporary data generated by the TNF probes. Prism's performance analysis generates large volumes of data, particularly for long-running programs or programs with high process counts. As a result, performance analysis can fail if insufficient disk space is available in the target directory. By default, Prism sets aside 128 Kbytes of storage in the target directory for TNF data. If 128 Kbytes is insufficient for your needs, you can increase the amount of the storage available by using the size parameter of the tnffile command.

If your trace buffer files are too small, once the buffer fills up your data will begin to overwrite older data in the trace buffer. If your trace buffer files exceed the size of your target directory, the data collection process will fail at that stage, before creating the final data file required by tnfview. When you have limited space available in your trace buffer directory, you can shorten the collection time using the tnfcollection command as an event action specifier (for further information about using the tnfcollection command as an event action specifier, see " Actions in Events") or you can limit the types of events collected using the tnfenable command (for further information about using the tnfenable command to selectively control which probes are enabled, see "Enabling Probes Selectively").

You can also define another location for the trace buffer files by setting an environment variable, PRISM_TNFDIR, to the location you choose. For example,

% setenv PRISM_TNFDIR /home/user/tnfdata/tmp

If you set PRISM_TNFDIR to an NFS-mounted directory, your performance analysis data will be affected by the extra time required for writing the data to non-local directories.