EXA performance

[Bernardo Innocenti]

Stefano Fedrigo wrote:

> Here are results of two runs of the cairo's performance test suite, at 16 and
> 24 bpp.  Test hardware is a B4, xserver-1.4-branch, cairo 1.4.10.  This time
> 24 bpp is overall better.

That's invaluable data, thank you!

> Only cairo_paint() is slower at 24, but not cairo_paint_with_alpha(), which is
> actually a lot faster.

Someone told me that some paths in pixman actually convert 16bpp scanlines
to a temporary 24bpp buffer, then do their work, then convert back to 16bpp.
If true, this would explain the observed slowness at 16bpp.

Aleph, could you post an oprofile of Sugar switching between zoom levels
in both 16bpp and 24bpp?  Doing it manually by pressing F1 to F4 would be
good enough for me: I just want to get an idea of where we spend the time.
Of course, X, amd_drv, pixman and cairo need to be built with -g.

-- 
   // Bernardo Innocenti - One Laptop Per Child
 \X/  http://www.codewiz.org/