Damage as a DIX notion

[Peter Harris]

On 2016-09-26 5:34 AM, Michel Dänzer wrote:
> On 26/09/16 11:23 AM, Keith Packard wrote:
>> A data-driven approach would be awesome here. Do we have a reasonable
>> performance metric? I'm no fan of gratuitous complexity, but text
>> performance is pretty important to me.
> 
> Here are some data points with the radeon driver using glamor on
> radeonsi. This is comparing the default configuration with Option
> "TearFree" (which uses extents based damage tracking as described in
> my other post):
> 
> 1: /tmp/baseline.txt
> 2: /tmp/tearfree.txt
> 
>        1                 2                 Operation
> ------------   -------------------------   -------------------------
>  194000000.0    148000000.0 (     0.763)   Dot 
>    9660000.0      9150000.0 (     0.947)   Char in 80-char aa line (Charter 10) 

I've found that careful use of the _mm_max_epi16/_mm_min_epi16
intrinsics pushes the cost for calculating the bounds of Dot down into
the noise. Presumably the non-Intel platforms have something similar in
their SIMD instruction sets too, but I'm not sure how "pixman" you want
to go on this.

Peter Harris
-- 
               Open Text Connectivity Solutions Group
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