On Tue, Mar 29, 2011 at 11:06:50PM +0100, Måns Rullgård wrote:
> Oskar Arvidsson <[email protected]> writes:
> 
> > Hi,
> >
> > On Tue, Mar 29, 2011 at 05:48:45PM +0200, Oskar Arvidsson wrote:
> >> Also, I've done some basic benchmarking on how this patchset affects
> >> 8-bit decoding. I'll post the data from those runs separately.
> >
> > Upon request by mru I extended the benchmark somewhat. I didn't bother
> > doing this with oprofile though.
> >
> > 10 runs decoding 8-bit h264:
> >
> >         |  Before           |  After
> > -------------------------------------------
> >         |  8.629            |  8.726
> >         |  8.606            |  8.709
> >         |  8.619            |  8.716
> >         |  8.609            |  8.683
> >         |  8.619            |  8.706
> >         |  8.606            |  8.786
> >         |  8.643            |  8.659
> >         |  8.626            |  8.653
> >         |  8.613            |  8.673
> >         |  8.629            |  8.733
> > -------------------------------------------
> > Avg:    |  8.62             |  8.70
> > Stddev: |  0.012            |  0.040
> > -------------------------------------------
> 
> Are those user time or elapsed time?

user

> 
> > From the table follows that the patchset gives a speed penalty to 8-bit
> > h264 decoding of about 1% (for this clip).
> 
> Note that the change is only slightly greater than one stddev of the
> after numbers.  It might be worthwhile testing another clip with
> different characteristics.

good point.

> Do you have any idea why it got slower?

For one, chroma dequant can't be inlined anymore. Also, h264.c handles
pixel size dynamically.

-- 
Oskar Arvidsson
+46 (0)701-766451
[email protected]

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