EXA performance

[Bernardo Innocenti]

Aleph has recently been doing some performance measurements
on the latest Xorg codebase, mostly concentrating on
bench.py and other micro benchmarks.

Performance of 16bpp VS 24bpp has been a hot topic recently.
We know 24bpp to be much faster for some operations (my
bench.py notably) and much slower for others (image puts),
but it's not clear which one is the overall winner
for our typical workload.

Jim would like to see some numbers in order to make a
decision.  Aleph, could you publish the results of x11perf
at least?  The Cairo perfomance suite would be even more
interesting to see.

Chris also wanted to see timing of a real-world Sugar
rendering... like switching between the 4 zoom levels.
That may require some (perhaps trivial) Sugar surgery, so
I'd leave it to one of the Python developers.

Oprofile and/or sysprof output while executing all the above
benchmarks would also provide invaluable information to find
out *why* things are being slow.  Aleph already has an
environment in place with all the components rebuilt
with debug symbols, so we can see the actual function calls
in the output.

Lastly, this thread may be generally interesting to
whoever is seeking to improve EXA performance on the XO:

 http://thread.gmane.org/gmane.comp.freedesktop.xorg/20111/focus=20116


-- 
  // Bernardo Innocenti
\X/  http://www.codewiz.org/