[cairo] Cairo 1.3 performance loss

[David Turner]

Sorry again, could you try the following patch, it should do the
trick with the -m flag. However, I don't think it may be merged into
the git repository right now, since the changes do change a few
measurements.

Hope this helps,

- David


On Thu, 01 Feb 2007 13:10:25 +0200, "Jorn Baayen" <jorn at openedhand.com> said:
> Hi,
> 
> On Thu, 2007-02-01 at 11:51 +0100, David Turner wrote:
> > > This still times individual iterations (but runs X of them and takes the
> > > median). The problem is that on this machine gettimeofday()'s
> > > granularity is too coarse to register any difference in time for many of
> > > the tests.
> > > 
> > 
> > Sorry for the confusion, here's a patch that adds a '-m' flag to cairo-perf
> > that can be used to specify test case multipliers. You can also define
> > the CAIRO_PERF_MULTIPLIER environment variable.
> 
> Unfortunately this doesn't help. Every test case does this:
> 
> cairo_perf_start ();
> do_something ();
> cairo_perf_stop ();
> return cairo_perf_elapsed ();
> 
> Now on ARM _start() and _stop() record the time using gettimeofday(),
> and _elapsed() takes the difference. But many tests run so quickly that
> they are done in less than a centisecond, which is all the timer 
> granularity there is here. This means the times get returned as 0, and
> adding together many zeroes doesn't help. 
> 
> To add a 'time many iterations in one go' mode, a timer would need to be
> added around the whole iterator, and that's perhaps not very elegant
> as we also have timing code inside the tests themselves ..
> 
> Sorry for the confusion!
> 
> Thanks,
> 
> Jorn
> 
> > 
> > Hope this helps,
> > 
> > - David
> -- 
> OpenedHand Ltd.
> http://o-hand.com/
> 
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