very bad, and very weird, scrolling text performance xorg 1.5.3 intel 2.5.1 GM965

Michel Dänzer michel at
Mon Dec 15 02:26:11 PST 2008

On Mon, 2008-12-15 at 10:57 +0100, Lukas Hejtmanek wrote:
> On Sun, Dec 14, 2008 at 06:48:52PM -0500, Thomas Jaeger wrote:
> > You really need the glyph cache in the X server to get decent text
> > performance out of the 2.5 intel driver.  The patches are pretty
> > straightforward to backport, but it is my understanding that a 1.6
> > server will be uploaded to jaunty soon, so you might want to wait for that.
> I wonder whether the Intel driver can get at least close to Nvidia driver.
> I ran x11perf on Nvidia system and Xserver *without* the glyph cache. Compared
> to these numbers, the Intel driver seems to be a bit comic with 56k glyphs/sec
> with EXA or 215k glyphs/sec with UXA.

Note that the glyph cache is specific to EXA, which the nvidia driver
doesn't use. UXA on the other hand may have the glyph cache in its copy
of the EXA code.

I'm not sure what's the bottleneck for the intel driver at this point,
the radeon driver easily gets 500k/s and beyond (which is still a far
cry from the numbers you measured, but already seems to mostly avoid it
being any practical limitation). Some of it may just be down to the
hardware (memory bandwidth, shader units etc.).

Earthling Michel Dänzer           |
Libre software enthusiast         |          Debian, X and DRI developer

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