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Old 03-31-06, 04:18 AM   #39
Unbuffered User
Join Date: Jun 2005
Posts: 388
Default Re: Slow AA text rendering in KDE

I have Mandrake 64-bit, KDE 3.5.1, and a 6800GT (2GB DDR500, 2.5GHz A64, blah blah blah)

With kwrite+AA, X usage just goes off the scale. If I were to guess, kwrite is redrawing way too much crap.

And when I turn off AA, instead kwrite cpu usage goes off the scale, though scrolling is much improved. This has to be a KDE/Qt problem. Most likely bad KDE programming. If I were energetic, I'd rebuild kde with konstruct and profile kwrite...

I have a 5900 and a 4200 right here. I'll give them a whirl.

edit: 4200, same issue. Not bothering to test the 5900, because...

... I get the *same* thing with the nv driver and vesa driver. Go harass KDE/Qt for a profile of kwrite. To demonstrate, open kwrite (AA off, nv or vesa driver) and hold down the "a" key for 30-40 characters, copy, and paste several times. kwrite simply comes to a halt at high kwrite cpu usage.

Now, for the driver "nvidia" + AA case, the rendering is offloaded to X for acceleration, and which really grinds the machine to a halt, which indicates X is poorly threaded probably.

Also, shrink kwrite down to minimum size, and note that the issue goes away. Obviously, ALL the text is redrawn every keystroke (or multiple times).

I've never really noticed this issue before, as I use Firefox and Emacs usually.

Don't make me bust out the Matrox G200 and test on that...

Last edited by xorbe; 03-31-06 at 05:18 AM.
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