:: choice ::
go green!  go red!  go blue!
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National Rifle Association
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"Anything cut to length will be too short. "
visit kde.org! visit debian.org!

benchmarking XRender performance, how to file nvidia bugs

Blauzahl asks where to file bugs we encounter in the nvidia drivers. Last night, after my previous blogentry Fredrik told me he disagreed that it's hard to find nvidia engineers that can help with this kind of performance problems. It seems some hang out in #xorg-devel, and our planet admin Chris Lee is currently working on the NVidia Linux team as well. Fredrik pointed me to a benchmark that measures the performance of various XRender calls. Running it shows that most of the tests are very fast (1 - 20 milliseconds) or very slow (most between 8 and 16 seconds). That means lots of operations take 400 times as long as others. On my notebook's ati x1300 using the fglrx driver, I get results of 20 milliseconds for the 'faster' operations. Not a single test takes more than 2.5 seconds. So nvidia is faster , but only for some tests. Overall, ATI performs better in these tests. And then maybe those operations can be accelerated in the driver. xrenderbenchmark takes ~13 minutes on my nvidia 7600GS and 1:45 on my ati x1300, a fairly low-end laptop chip. In order to compile xrenderbenchmark, first "qmake xrenderbenchmark.pro" (make sure you use Qt4's qmake). Then run make, and xrenderbenchmark.

So if you encounter those performance problems, get Zack's benchmark and provide the data to the nvidia developers. The problems should be filed as a bug on the product xorg, component "Driver/nVidia (proprietary)" on bugs.freedesktop.org. I've filed the performance issues here, along with some my logfiles.

Update: I'm not the first finding out about this. Nice pictures showing the performance problems and lots of reports on the Phoronix forums. All reporting abominable 2d performance with NVidia graphics cards and drivers.

[ Fri, 27 Jun 2008 06:20:12 +0200 ] permanent link

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