Profiling redraws with Xorg 1.5.99.3

[Peter Clifton]

On Fri, 2008-12-26 at 16:53 +0100, Erik Andrén wrote:
> 2008/12/26 Peter Clifton <pcjc2 at cam.ac.uk>:
> > Hi guys,
> >
> > I've been profiling some speed differences rendering pixel aligned
> > (should be fast-path) cairo drawing, and happened across the fact that
> > for my redraw test (which is running flat out), 13% of my total system
> > time is spent in dixLookupPrivate.
> >
> > Is there anything which can be done to avoid the overhead of
> > dixLookupPrivate?
> >
> > The overhead is spread over a number of callers, the top few being:
> >
> > exaPixmapIsOffscreen (Total 3.43%)
> > exaDoMoveInPixmap    (Total 1.82%)
> > exaDoMigration       (Total 1.17%)
> >
> > Now whether this is simply because my cairo rendering is slow, and
> > causing lots of migration I don't know.. but I thought it would be of
> > interest here.
> >
> > This is made with the Intel driver at the tip of the 1.6 branch, using
> > EXA acceleration.
> >
> > Best wishes,
> >
> 
> Perhaps you're struck by this bug:
> http://bugs.freedesktop.org/show_bug.cgi?id=16647

Could be. Shame the new optimised implementation of the private lookup
had to be reverted on the 1.5 branch.

I'm running 1.5.99, and it would appear that the patch is applied. It is
a shame dixLookupPrivate is consuming so many cycles still.

The patch for the performance issue is not applied on the server I'm
using, so I'll try applying that and rebuilding. Thanks for the pointer!

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)