[Pixman] ARM iwmmxt patches
sandmann at cs.au.dk
Wed Aug 31 05:12:13 PDT 2011
Matt Turner <mattst88 at gmail.com> writes:
> I've been trying to figure out if the ARM iwmmxt inline assembly makes
> any difference at all. I think the conclusion is that it does not.
> Updated code is here:
You mean that inline assembly in mmx_fill() doesn't make a difference?
The lowlevel-blt benchmark doesn't hit the fill and blt routines at all,
so this data doesn't support the conclusion that inline assembly in
mmx_fill() and mmx_blt() makes no difference.
> Never does using inline assembly seem to make any sort of meaningful
> difference over simply compiling pixman-mmx.c for ARM/iwmmxt. I tried
> checking the alignment in the 'wip' commit in the blt function to
> avoid a lot of unnecessary walign instructions, but as you can see
> from the benchmark results, it doesn't help anything.
The cairo-trace tests are better benchmarks to use in general because
they reflect real-world use. lowlevel-blt-bench really should only be
used for the case where you are optimizing a specific compositing
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