the mysterious cairo-perf (was: Re: [cairo] [PATCH] Performance patch for bo intersections)

Behdad Esfahbod behdad at
Fri Dec 15 21:09:14 PST 2006

On Thu, 2006-12-14 at 13:11 -0500, Carl Worth wrote:
> but I
> have occasionally seen entirely inexplicable results that are
> obviously "too fast" to be "real".) 

Yes, this happens a lot.  Basically anything that runs for shorter than
a few seconds cannot be considered accurate.  Also note that
gettimeofday() has a limited accuracy.  A few years ago I added some
timing to glxgears, and I observed gettimeofday() return the same value
before and after a frame redraw.  Adding a sched_yield() fixed it there,
but you probably don't want to do that :).


"Those who would give up Essential Liberty to purchase a little
 Temporary Safety, deserve neither Liberty nor Safety."
        -- Benjamin Franklin, 1759

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