[cairo] pixman: New ARM NEON optimizations

Koen Kooi k.kooi at student.utwente.nl
Tue Feb 16 11:23:14 PST 2010

Hash: SHA1

On 16-02-10 18:37, Siarhei Siamashka wrote:
> On Tuesday 16 February 2010, Koen Kooi wrote:
>> On 16-02-10 16:56, Siarhei Siamashka wrote:
>>> On Thursday 05 November 2009, Chris Wilson wrote:
>>>> 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.
>>> Here is a result of running a standard set of cairo-perf-trace tests on
>>> 600MHz ARM Cortex-A8 with 128MB RAM (beagleboard B7):
>>> http://people.freedesktop.org/~siamashka/files/20100216/pixman-0.17.6/
>> Thanks for putting that together! Would it be possible to mark fastpaths
>> with a different colour/border? That would picking slowpaths from the
>> picture a lot easier :)
> It's just a standard callgraph generated by this script:
> http://code.google.com/p/jrfonseca/wiki/Gprof2Dot
> Tweaking it and additionally highlighting some important functions
> is probably possible. But the people who are familiar with the code,
> can see performance problems even without such highlighting :)
> On the other hand, end users may have some use cases which run
> slow, but they don't have any easy way to check whether pixman has
> all the needed optimizations for it already or not. Or whether there could
> be some other performance bottleneck on the boundary between different
> components/libraries or anything else.

The get_scanline_32 seems to get hit a lot, wasn't there a fastpath
already for that?


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