[Pixman] [PATCH 3/3] Add SSSE3 fast path skeleton

[Siarhei Siamashka]

On Wednesday 08 December 2010 16:13:48 Liu Xinyun wrote:
> There is a performance test between commits
> commit 56777f3f675869806cd30bcd21a5b39d788507cb
> Author: Dmitri Vorobiev <dmitri.vorobiev at movial.com>
> Date:   Wed Sep 22 12:34:57 2010 +0300
> 
>     Use <sys/mman.h> macros only when they are available
> 
> commit 3d094997b1820719d15cec7dc633ed37e1912bfc
> Author: Siarhei Siamashka <siarhei.siamashka at nokia.com>
> Date:   Tue Nov 30 00:31:06 2010 +0200
> 
>     Fix for potential unaligned memory accesses

Right, if we look at the changes between these two commits:

> new: ba69989374fe9cbe5151c5aac7b824da0806f94a
> Speedups
> ========
> image-rgba                  ocitysmap-0    7476.29 (7520.52 3.09%) ->
> 6817.63 (6822.39 3.04%):  1.10x speedup ▏
> image-rgba                    poppler-0    15028.69 (15029.97 0.71%) ->
> 13748.83 (13793.77 0.91%):  1.09x speedup ▏
> image-rgba         gnome-terminal-vim-0    23378.23 (23494.57 0.70%) ->
> 21916.17 (21926.92 0.52%):  1.07x speedup ▏
> image-rgba          xfce4-terminal-a1-0    16632.31 (16637.27 0.60%) ->
> 15630.85 (15650.89 0.63%):  1.06x speedup ▏
> image-rgba       firefox-planet-gnome-0    87751.74 (87809.43 0.18%) ->
> 82620.93 (82949.20 0.27%):  1.06x speedup
> 
> image-rgba          firefox-talos-gfx-0    51169.66 (51542.49 0.36%) ->
> 48572.45 (48610.13 0.26%):  1.05x speedup
> 
> image-rgba         swfdec-giant-steps-0    11619.84 (11646.91 0.46%) ->
> 11056.41 (11057.69 0.40%):  1.05x speedup

Removal of software prefetch provides a good performance improvement. It was a
nice catch, thanks for that patch. But as a side effect, it also makes SSE2
optimizations more competitive and somewhat harder to beat by SSSE3.

> new: 1ca715ed1e6914e9bd9f050065e827d7a9e2efc9
> Slowdowns
> =========
> image-rgba          firefox-talos-svg-0    177350.25 (181525.48 1.11%) ->
> 198170.08 (202124.06 0.96%):  1.12x slowdown ▏
> image-rgba             swfdec-youtube-0    15843.51 (15850.03 0.76%) ->
> 18104.51 (18224.94 0.40%):  1.14x slowdown ▏

> new: 1d4f2d71facd5f2bbce74fbe3407ccea6cf4bea1
> Slowdowns
> =========
> image-rgba          firefox-talos-svg-0    197582.42 (202455.51 1.19%) ->
> 208636.52 (212057.02 0.90%):  1.06x slowdown

And these two slowdowns are caused by the changes in radial gradients code.
I guess it can't be helped because now radial gradients are supposed to be more
correct.

-- 
Best regards,
Siarhei Siamashka