Profiling redraws with Xorg 1.5.99.3

Peter Clifton pcjc2 at cam.ac.uk
Fri Dec 26 07:46:00 PST 2008


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,

-- 
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!)




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