Stats accuracy
Mark Visconti (visconti++at++cis.ohio-state.edu)
Fri, 21 Oct 1994 20:40:58 -0400 (EDT)
I have a question regarding the accuracy of some of the data
displayed by the channel statistics. The data in question is the
frame rate information displayed at the top left corner of the statistics.
It usually reads X/Y where X is the current frame rate (averaged over
a time period) and Y is the value specified in pfFrameRate(). I'm using
1 second for the time period (I've also tried 2 if I remember).
The application I am running is on a 3 pipe MCO'd Onyx set up so
that there are 6 channels(2 per pipe) stacked vertically, each at a resolution
of 1280x1024. 7 processors are allocated by Performer, the remaining
process(data collection) is sync'ed to the app process through the use of
barriers. The app process gets the present time and communicates it to the
data collection process through shared memory. Okay, now the discrepancy.
While the value displayed by the channel statistics states 30Hz (the frame
rate is set to 60fps), the data collection process states 60Hz consistently
(I save the time for each frame - it's definitely 16.7 ms/frame).
What am I missing or assuming incorrectly? The phase is FIXED. I noticed
running FREE actually resulted in a lower frame rate(30 Hz) reported by
channel statistics and according to pfGetTime() deltas.
Thanks for any help supplied,
Mark Visconti
visconti++at++cis.ohio-state.edu
LTSI, WPAFB, Dayton, OH
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