[cairo] pixman: New ARM NEON optimizations

Chris Wilson chris at chris-wilson.co.uk
Thu Nov 5 01:26:56 PST 2009

Excerpts from Siarhei Siamashka's message of Wed Nov 04 16:36:21 +0000 2009:
> In any case, simple functions which use only basic data types as arguments
> (nothing like pixman_image_t) and has no checks for clipping or whatever
> else can be used from the other libraries efficiently.

+1. ;-)

I could also use a pixman-core, though the overhead after applying
Søren's flags branch is not large enough to justify the effort, yet.

> Things to do next:
> * finetune performance for some of the functions
> * add GDK pixbuf related fast path functions
> * try to reduce dispatch overhead in pixman-arm-neon.c (maybe adding some
> probably autogenerated code with if/else/switch/case mess in
> arm_neon_composite to decide which NEON fast path function can be used instead
> of calling _pixman_run_fast_path can reduce a bit of overhead).

Before going too far along the performance, make sure you are also
checking with Søren's work in reducing overheads.

Also I'm very interested in seeing what the profiles look like for
pixman and cairo on ARM. Just knowledge of the behaviour of your target
applications would be useful when thinking about how to tune cairo.
Chris Wilson, Intel Open Source Technology Centre

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