[Pixman] [RFC] Performance reporting capabilities for pixman?

Soeren Sandmann sandmann at daimi.au.dk
Mon Sep 27 21:01:55 PDT 2010

Siarhei Siamashka <siarhei.siamashka at gmail.com> writes:

> Let's face it, I think the end users rarely report performance problems in
> pixman unless the performance is really notoriously bad (and not ignored
> because "it's software rendering, so it is expected to be slow"). Finding real 
> performance bottlenecks in pixman requires running a profiler and being able to
> actually interpret its logs.

Yeah, in fact almost all users never report *anything* unless it's so
broken that they can't possibly work around it. They have been trained
to do this because many projects simply ignore bugs for years in some
cases, and because bugzilla is a huge pain to deal with.

> I wonder if it would make sense to add an extra configure option for the
> special profiling enabled pixman build which would do:
> 1. Avoid caching fast path lookup failures
> 2. Once hitting slow path, record the type of operation, image color formats
> and image flags.
> 3. For each unique slow path variant, accumulate the number of times it got
> hit, the total number of (destination?) pixels which got processed, the total
> number of scanlines.
> 4. Once per N minutes, spam into syslog with the current accumulated 
> statistics.

This all makes sense to me. It might even be interesting to have it
compiled in by default, but disabled unless it is turned on through an
environment variable.


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