[Pixman] [PATCH 0/2] 7-bit bilinear interpolation precision

[Matt Turner]

On Mon, Jun 25, 2012 at 7:44 PM, Siarhei Siamashka
<siarhei.siamashka at gmail.com> wrote:
> These are the test patches for switching to 7-bit bilinear
> interpolation precisions. The first patch makes bilinear precision
> configurable. The second patch tweaks SSE2 bilinear scaler for better
> performance using PMADDWD instruction. Both should be applied after:
>    http://lists.freedesktop.org/archives/pixman/2012-June/002074.html
>
> Compared to pixman-0.26.0, bilinear src_8888_8888 operation
> becomes almost 1.8x faster on Core i7. The firefox-fishtank trace
> gets ~30% speedup, which should help a bit with:
>    http://lists.freedesktop.org/archives/pixman/2012-May/001942.html
> Also 7-bit bilinear interpolation precision still allows a nice SSSE3
> optimization, which can be implemented later to get even more speed.
>
> But the patches need a lot more testing on different hardware.

These patches work for me. I've also gotten pmaddwd working on MMX,
which I'll send out after some more testing and benchmarks. It
replaces 4 unpacks, 4 multiplies, and 2 adds with 2 unpacks and two
madds.

Thanks Siarhei!

Matt