[cairo] More info about fbCompositeCopyAreammx

Vladimir Vukicevic vladimir at pobox.com
Thu Mar 27 13:00:05 PDT 2008

On Mar 27, 2008, at 11:51 AM, Frédéric Plourde wrote:
> Remember that issue you brought up about subimage_copy with 512X512  
> which made things slower ?
> I've got some more news about it...
> Since Soeren questionned the precision of giving perf results with  
> only a small number of iterations, I've used a minimum of 100  
> iterations on my perf tests.
> Take a look at the newest results about "subimage_copy"...
> http://pastebin.mozilla.org/383418
> First group of results shows NO GAIN between  pre-mmx and post-mmx  
> versions
> except for the 512X512 case alone, which shows 58% speedup... that's  
> weird
> The second group of results shows perf GAINS between :  before  
> applying my patch and after applying my "fbCompositeCopyArea" patch
> But these gains, as you noticed earlier, seem to fade out as the  
> image scales up.
> I'll investigate some more about that, but for now, I think the  
> patch "pixman_OPT_MMX_addFastPath_to_fbCompositeCopyAreammx.patch"  
> is worth it.

Sounds good to me -- Soeren, adding an x8r8g8b8 -> a8r8g8b8 SOURCE  
path being a Copy sounds sane, right?  Fred, I notice that your patch  
only adds that path for the MMX case, but the same path can be added  
for non-MMX also, I think.

     - Vlad

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