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Subject: -38- Timing on pre-1992 platforms
Date: 8 Apr 94 00:00:01 EST
Several libpf functions require high-resolution timing information.
On most recent machines (Indy, Indigo, Indigo2, 4D/35 and Onyx) and
PowerSeries or Crimson machines with IO3 boards, IRIS Performer
uses special hardware counters with sub-microsecond resolution.
(The IO3 board was standard on Crimson and later 4D/300 and 4D/400
machines. You can check for it with the hinv(1M) command.)
On older platforms, for example, those with IO2 boards, the
time-of-day clock is used, which, by default, has a 10 ms
resolution. This resolution is inadequate for many libpf functions,
including animation sequences (pfSequence), graphics load
computation (pfChanStress), and the display of accurate channel
statistics (pfDrawChanStats). On these machines, you may want to
enable fast timers using systune(1M) to set the fasthz variable.
See the man page for timers for more information. Frame rate
control is poor on machines that lack both a fast clock and the
video clock used by pfVClockSync.
Up: SGI performer Frequently Asked Questions (FAQ)
Next: -39- 2.0 Warnings from ld when building on IRIX 6.2
Previous: -37- Frame control on low- and mid-range machines