render improvements

Adam Jackson ajax at
Fri Apr 15 17:14:42 PDT 2005

On Friday 15 April 2005 10:10, Lars Knoll wrote:
> Hi,
> Zack and myself have in the last two weeks worked on improving performance
> the general composition path in the render extenstion (the code in
> fbcompose.c).

Nice work!

This fails rendercheck (from /cvs/xapps) for a few transformations and for the 
component alpha case.  I don't know whether that's a bug in your code or in 
rendercheck but we should verify it.

The benchmark numbers you posted look good for the general case but are 
marginally slower for Over blends, which will probably be 90% of Render 
usage.  I suspect this is a result of not using the MMX path.

Xvfb performance (as measured with raster's render_bench) is merely about 
twice as fast as before for untransformed operations.  This is disturbing.  
Either Xvfb is naive or Xephyr is clever, because Xvfb should in principle be 
faster, host memory always being faster than the AGP bus.

Interesting that it's almost exactly the same speed at both 16bpp and 32bpp.

- ajax
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