[gst-devel] rdtscll()'s role

Erik Walthinsen omega at cse.ogi.edu
Fri May 12 04:45:04 CEST 2000


On Thu, 11 May 2000, Myers W. Carpenter wrote:

> 	Erik said it was to count how many cycles the processor had done since
> boot up.  Why gstreamer needs to know this I don't know.
This is highly useful for detailed benchmarks.  Grab cycle count, do
something, grab cycle count, subtract.  It's cycle-accurate, so when I'm
working on MMX code where the cycles/sample works out down to the 1/16ths,
it's quite handy.  To answer the specific question, it doesn't really need
it.  This use of it could just as easily be replaced by gettimeofday(),
though that's more expensive.

         Erik Walthinsen <omega at cse.ogi.edu> - Staff Programmer @ OGI
        Quasar project - http://www.cse.ogi.edu/DISC/projects/quasar/
   Video4Linux Two drivers and stuff - http://www.cse.ogi.edu/~omega/v4l2/
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