[cairo] SSE support in pixman

[Frédéric Plourde]

Hi André !

My name if Frederic Plourde (Fplourde on irc - "freenode" server, 
"cairo" channel, by the way... if you wanna join ;-))
I'm working with mozilla and I've been working on mmx for some time now.

   Sorry I didn't answer sooner to you email, I was out of town for the 
last 3 days.
Indeed, the mmx and sse projects are running and we intend to optimize 
pixman as much as we can until next version of firefox.

When you came in 3 or 4 days ago, I was a little surprised to discover 
you had been working on the exact same things as I was working on. But I 
can't complain... your contributions will sure help pixman perform 
faster.  The only thing is : I really hope we'll manage to cooperate 
efficiently on mmx and sse2 optimizations as I intend to keep in touch 
with your team on a regular basis.  :-)

Best,
-fred-

P.S. - I saw you preliminary results, attached to your email... And I 
was wondering about the very high standard deviations you got ... 
something like 30%... It's quite high.. Do you have any insight on what 
could explain it ?



André Tupinambá a écrit :
> Hi everyone,
>
> I just subscribe this mailing list and saw some archives about SSE(2)
> optimization in pixman library. Are this (sub)project running?
>
> I'm studing the pixman some days and I think that I can help too. So I
> wrote a proof of concept changing the fbCompositeSrc_8888x8888mmx to
> use SSE2 instructions.
>
> In attachment there are the patch and some cairo-perf's results. I
> don't know much about the autoconf tool so to compile the code I
> needed to run the configure like this:
>
> CFLAGS=-msse2 ./configure
>
> And them change the config.h file to include this:
>
> #define USE_SSE 1
>
> The firsts tests results are REALLY good, but I'm not sure that's
> works fine and not introduce some bad pixels in the result images. The
> perf was runned using:
>
> taskset 2 ./cairo-perf -i 500 paint_image_rgba_over > perf-sse2-run1
>
> Best Regards
>
> André Tupinambá
>
> PS: If you saw anything weird in my English, please forgive me. I'm
> from Brazil and English ain't my first language. Well, the comments
> are LGPL too, fell free to fix them :)
>   
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