[Pixman] [PATCH 0/4] More VMX enhancements

[Pekka Paalanen]

On Thu, 10 Sep 2015 11:55:56 +0300
Oded Gabbay <oded.gabbay at gmail.com> wrote:

> On Mon, Sep 7, 2015 at 2:09 PM, Oded Gabbay <oded.gabbay at gmail.com> wrote:
> 
> > On Mon, Sep 7, 2015 at 2:04 PM, Pekka Paalanen <ppaalanen at gmail.com>
> > wrote:
> > > On Sun,  6 Sep 2015 18:27:07 +0300
> > > Oded Gabbay <oded.gabbay at gmail.com> wrote:
> > >
> > >> This patch-set contains optimizations for two existing VMX fast-paths
> > and a new
> > >> VMX fast-path function.
> > >>
> > >> The optimization ideas came from Siarhei's recent implementation of
> > over_n_8888
> > >> VMX fast path (see
> > http://lists.freedesktop.org/archives/pixman/2015-September/003951.html).
> > >>
> > >> The new function I added is actually one that I already implemented a
> > couple
> > >> of months ago, but it produced conflicting results regarding the
> > performance.
> > >> However, I now optimized it and it now shows considerable performance
> > >> improvement over the non-vmx path.
> > >>
> > >> The last patch removes many helper functions that caused the less than
> > stellar
> > >> performance the current fast-paths provide. I removed them as I don't
> > want
> > >> anyone to try and use them, because there are much better alternatives,
> > as
> > >> I've demonstrated with this patch-set.
> > >>
> > >> Thanks,
> > >>
> > >>       Oded
> > >>
> > >> Oded Gabbay (4):
> > >>   vmx: optimize scaled_nearest_scanline_vmx_8888_8888_OVER
> > >>   vmx: optimize vmx_composite_over_n_8888_8888_ca
> > >>   vmx: implement fast path vmx_composite_over_n_8_8888
> > >>   vmx: Remove unused expensive functions
> > >>
> > >>  pixman/pixman-vmx.c | 439
> > ++++++++++++++++++----------------------------------
> > >>  1 file changed, 150 insertions(+), 289 deletions(-)
> > >>
> > >
> > > Hi Oded,
> > >
> > > nice diffstat. :-)
> > >
> > > This series is:
> > > Acked-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> > >
> > > I did notice a few minor issues. Patch 1 has a dereference before
> > > NULL-check, and you sometimes forget the space before an opening
> > > parenthesis.
> > >
> > > I suppose there is no danger of regressing operations you didn't
> > > touch? ;-)
> > >
> > >
> > > Thanks,
> > > pq
> >
> > HI Pekka,
> > I run cario benchmark (trimmed) and there was *no* regression.
> > I don't think optimizing some fast-paths affects other, non-related,
> > fast-paths. And, of course, I don't think it has *any* impact on non
> > POWER systems.
> > However, if someone thinks of a specific other function I need to
> > check for regression, I'm open for suggestions :)
> >
> >          Oded
> >
> 
> ​It bugged me that there was no change, neither up nor down in cairo
> benchmark.
> So I rechecked it and I had a wrong setup - cairo used the system-installed
> pixman instead of my pixman.
> 
> After fixing that, I saw several modest speedups for this patch series:
> 
> Speedups
> ========
> image        t-firefox-scrolling  1232.30 (1237.81 0.40%) -> 1080.17
> (1097.06 0.99%):  1.14x speedup
> image        t-gnome-terminal-vim  613.86 (615.04 0.12%) -> 549.73 (551.32
> 0.13%):  1.12x speedup
> image        t-evolution  405.54 (412.06 0.81%) -> 370.57 (379.11 1.89%):
>  1.09x speedup
> image        t-gvim  653.02 (655.16 0.16%) -> 615.31 (618.40 1.68%):  1.06x
> speedup
> image        t-firefox-talos-gfx  919.31 (926.31 0.36%) -> 867.05 (870.01
> 0.35%):  1.06x speedup
> ​
> I'll add it into the last commit of this patch-set for future references.

Paranoia pays off!


Cheers,
pq
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