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# The Perf SPU

Chromium has an additional SPU that is capable of taking snapshots of the current state of certain aspects of how everything is performing, this is the Perf SPU.

Currently we have two mechanisms in which to obtain performance counters. These are frame based (i.e. via SwapBuffers) or timer based. To set Chromium up for this performance criteria, in your applications, we can issue the commands:

- glChromiumParameterfCR(GL_PERF_START_TIMER_CR, 5.0); or
- glChromiumParameteriCR(GL_PERF_SET_DUMP_ON_SWAP_CR, 1000);

The first of these will start timer on a five second interval counting vertex statistics through SwapBuffers, and dump the relevant statistics on every fifth second. The second will dump the statistics on every 1000'th frame (again through SwapBuffers).

NOTE: To stop the timer at any time, issue:

- glChromiumParameterfCR(GL_PERF_STOP_TIMER_CR, 0.0);

The statistics themselves are dumped to a log file. This can be stderr, stdout or a log file specified through the startup python script. Some examples:

- clientperfspu.Conf( 'log_file', '/tmp/%H_perf.log' )
- clientperfspu.Conf( 'log_file', 'stdout' )

The %H is expanded into the hostname of the running node. This approach doesn't allow a unified logfile in which to output these statistics, so instead - we can use the mothership in which to dump data back to which collates all perfSPU data.

- clientperfspu.Conf( 'mothership_log', '1' )

In addition to setting the above, you must also set the logfile in which the mothership should 'append' data. This is defined through an environment variable - CR_PERF_MOTHERSHIP_LOGFILE, which should define the full path and logfile to output all incoming data.

NOTE: Using the mothership logging facility will disable the 'log_file' ability.

Additional helper functions for use with the performance SPU are:

- clientperfspu.Conf( 'dump_on_swap_count', '1000' )
- clientperfspu.Conf( 'dump_on_finish', '1' )
- clientperfspu.Conf( 'dump_on_flush', '1' )
- clientperfspu.Conf( 'token', '1' )

Equivalent functions (from above) that are accessible to applications:

- glChromiumParameteriCR(GL_PERF_SET_DUMP_ON_SWAP_CR, 1000);
- glChromiumParameteriCR(GL_PERF_SET_DUMP_ON_FINISH_CR, 1);
- glChromiumParameteriCR(GL_PERF_SET_DUMP_ON_FLUSH_CR, 0);
- glChromiumParametervCR(GL_PERF_SET_TOKEN_CR, "HeadSPU");

The last one of these above - token, gives the ability to attach an extra string to each line of the output. This is useful to identify certain statistics that are defined as 'interesting'.

We can also issue a request to the perfSPU to dump our statistics on demand, through:

- glChromiumParameteriCR(GL_PERF_DUMP_COUNTERS_CR, 0);

Finally, to interact with the statistics that the perfSPU is monitoring, we can use:

- PerfData *framedata;
- glChromiumGetParametervCR(GL_PERF_GET_FRAME_DATA_CR, {spuid}, 0, 0, data);

or

- PerfData *timerdata;
- glChromiumGetParametervCR(GL_PERF_GET_TIMER_DATA_CR, {spuid}, 0, 0, data);

Both of these will return pointers to the data structures used in the perfSPU itself. Look in include/cr_perf.h for the information provided. Using this information, you can reset, or tweak, the data that the perfSPU is monitoring.

Finally, to ensure the data is collected right to the end of the process that's running - be sure to issue a SIGTERM to the application (not crappfaker). This will ensure the SPU chain is shutdown cleanly and all data dumped to the logfile.

Current sample output from atlantis, running with four crserver processes and with the tilesortSPU, on different nodes follows:

    HeadSPU redhat FRAMESTATS 1000 POLYGONS 576000 576000
    HeadSPU redhat FRAMESTATS 1000 glVertex3fv 1859000 1859000
    HeadSPU redhat FRAMESTATS 1000 INTERP_TRIS 461000 461000
    HeadSPU redhat FRAMESTATS 1000 INTERP_QUADS 107000 107000
    HeadSPU redhat FRAMESTATS 1000 INTERP_POLYGONS 8000 8000

    sabrewulf FRAMESTATS 1000 POLYGONS 161153 161153
    sabrewulf FRAMESTATS 1000 glVertex3fv 518826 518826
    sabrewulf FRAMESTATS 1000 glVertex4fv 1214 1214
    sabrewulf FRAMESTATS 1000 INTERP_POINTS 374 374
    sabrewulf FRAMESTATS 1000 INTERP_LINES 1664 1664
    sabrewulf FRAMESTATS 1000 INTERP_TRIS 126422 126422
    sabrewulf FRAMESTATS 1000 INTERP_QUADS 31364 31364
    sabrewulf FRAMESTATS 1000 INTERP_POLYGONS 1936 1936

    aticatac FRAMESTATS 1000 POLYGONS 281181 281181
    aticatac FRAMESTATS 1000 glVertex3fv 908531 908531
    aticatac FRAMESTATS 1000 glVertex4fv 2048 2048
    aticatac FRAMESTATS 1000 INTERP_POINTS 652 652
    aticatac FRAMESTATS 1000 INTERP_LINES 2741 2741
    aticatac FRAMESTATS 1000 INTERP_TRIS 218043 218043
    aticatac FRAMESTATS 1000 INTERP_QUADS 57149 57149
    aticatac FRAMESTATS 1000 INTERP_POLYGONS 3620 3620

    pssst FRAMESTATS 1000 POLYGONS 156371 156371
    pssst FRAMESTATS 1000 glVertex3fv 503225 503225
    pssst FRAMESTATS 1000 glVertex4fv 1422 1422
    pssst FRAMESTATS 1000 INTERP_POINTS 711 711
    pssst FRAMESTATS 1000 INTERP_LINES 1509 1509
    pssst FRAMESTATS 1000 INTERP_TRIS 122894 122894
    pssst FRAMESTATS 1000 INTERP_QUADS 29786 29786
    pssst FRAMESTATS 1000 INTERP_POLYGONS 2182 2182

    jetpack FRAMESTATS 1000 POLYGONS 279325 279325
    jetpack FRAMESTATS 1000 glVertex3fv 902115 902115
    jetpack FRAMESTATS 1000 glVertex4fv 2580 2580
    jetpack FRAMESTATS 1000 INTERP_POINTS 1290 1290
    jetpack FRAMESTATS 1000 INTERP_LINES 2615 2615
    jetpack FRAMESTATS 1000 INTERP_TRIS 217065 217065
    jetpack FRAMESTATS 1000 INTERP_QUADS 55445 55445
    jetpack FRAMESTATS 1000 INTERP_POLYGONS 4200 4200

    HeadSPU redhat SPUID 0 CONNECTION ID 0 PORT 7000 TOTAL_BYTES RECEIVED 17020
    HeadSPU redhat SPUID 0 CONNECTION ID 0 PORT 7000 TOTAL_BYTES SENT 15816964
    HeadSPU redhat SPUID 0 CONNECTION ID 1 PORT 7001 TOTAL_BYTES RECEIVED 17020
    HeadSPU redhat SPUID 0 CONNECTION ID 1 PORT 7001 TOTAL_BYTES SENT 28437708
    HeadSPU redhat SPUID 0 CONNECTION ID 2 PORT 7002 TOTAL_BYTES RECEIVED 17020
    HeadSPU redhat SPUID 0 CONNECTION ID 2 PORT 7002 TOTAL_BYTES SENT 15535012
    HeadSPU redhat SPUID 0 CONNECTION ID 3 PORT 7003 TOTAL_BYTES RECEIVED 17020
    HeadSPU redhat SPUID 0 CONNECTION ID 3 PORT 7003 TOTAL_BYTES SENT 28104632
    HeadSPU redhat SPUID 0 TOTAL FRAMES 1060
    HeadSPU redhat SPUID 0 TOTAL CLEARS 1061

    sabrewulf SPUID 2 CONNECTION ID 2 PORT 7000 TOTAL_BYTES RECEIVED 15816964
    sabrewulf SPUID 2 CONNECTION ID 2 PORT 7000 TOTAL_BYTES SENT 17020
    sabrewulf SPUID 2 TOTAL FRAMES 1060
    sabrewulf SPUID 2 TOTAL CLEARS 1061

    aticatac SPUID 4 CONNECTION ID 2 PORT 7001 TOTAL_BYTES RECEIVED 28437708
    aticatac SPUID 4 CONNECTION ID 2 PORT 7001 TOTAL_BYTES SENT 17020
    aticatac SPUID 4 TOTAL FRAMES 1060
    aticatac SPUID 4 TOTAL CLEARS 1061

    pssst SPUID 6 CONNECTION ID 2 PORT 7002 TOTAL_BYTES RECEIVED 15535012
    pssst SPUID 6 CONNECTION ID 2 PORT 7002 TOTAL_BYTES SENT 17020
    pssst SPUID 6 TOTAL FRAMES 1060
    pssst SPUID 6 TOTAL CLEARS 1061

    jetpack SPUID 8 CONNECTION ID 2 PORT 7003 TOTAL_BYTES RECEIVED 28104632
    jetpack SPUID 8 CONNECTION ID 2 PORT 7003 TOTAL_BYTES SENT 17020
    jetpack SPUID 8 TOTAL FRAMES 1060
    jetpack SPUID 8 TOTAL CLEARS 1060