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Old 03-07-08, 02:23 PM   #157
hyfans
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Default Re: Slow AA text rendering in KDE

beta driver 171.06 !!! the new text aa acceleration is great, please give it a try.


test on Ubuntu Studio 8.04 (030608 dailybuild+update to the latest package).
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Old 03-07-08, 02:42 PM   #158
Linuxhippy
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Default Re: Slow AA text rendering in KDE

Quote:
Setting up acceleration engine for small things like rendering text characters is like using big gun to kill the fly.
This is simply wrong. The intel-driver team reported that even for 10x10 pixel areas blits are about 2x faster when done by the GPU, which is exactly in the reange which glyphs have.

However this was only for blits - where the destination is completly overwritten. Stuff like subpixel-AA'es fonts need to know whats "behind" the character they are drawing to compute the actual result which means the would have to read the area where the text should be rendered to from Video-RAM back into System-Ram and download it to the card again.
This is where the "software" slowness comes from.


Quote:
Cleartype is 100% rendered in software on CPU. Nvidia tries to accelerate as much as possible in Linux.
Where do you know that cleartype is rendered "100%" in software?
At least Sun was able to accalerate it using GLSL shaders when using their OpenGL pipeline in a cross-GPU manner and they did reach good results.
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Old 03-08-08, 02:28 AM   #159
Plagman
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Default Re: Slow AA text rendering in KDE

Please see: http://www.nvnews.net/vbulletin/showthread.php?t=109422
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Old 03-08-08, 02:50 AM   #160
tier
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by Plagman
Works really great on my nvs 140m!
Good work
Thank you very much :-)

Edit: I have the impression that everything is much more responsive now than it was with the older drivers. Great improvement!
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Old 03-08-08, 08:45 AM   #161
Linuxhippy
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Default Re: Slow AA text rendering in KDE

Is there any technical reson why this improvement is only supported on GF8 and higher (according to the post)?
I've a GeForce6600 which also suffers from slowness in 2D mode, especially for graphical applications that use the Render extension a lot (FireFox3, QT4 applications, ...).

The reason I wonder is because Sun was able to accalerate subpixel-aa using OpenGL in a cross-GPU manner (the code works well on GF5xxx and higher as well as ATI-9600+), whereas the nvidia driver restricts it to GF8 and higher.
Are older GPUs planned to be supported later?

lg Clemens
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Old 03-08-08, 09:53 AM   #162
gribelu
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Default Re: Slow AA text rendering in KDE

Same slowness here on a 6600GT .. Fix this pleaase
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Old 03-09-08, 03:01 AM   #163
evanlec
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Default Re: Slow AA text rendering in KDE

this glyph cache feature seems great and all, but im not sure if its having any effect...
is there a way to see whether it is enabled (i set the nvidia-settings -a Glyph_Cache=1 string), and if so whether its doing anything or not?

Thanks for paying attention to this btw

(8800 GTS with NVIDIA 171.06 driver, kernel 2.6.24.3)
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Old 03-09-08, 03:57 AM   #164
Dragoran
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Default Re: Slow AA text rendering in KDE

you have to set InitialPixmapPlacement to 2 too.
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Old 03-09-08, 01:02 PM   #165
zbiggy
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by Linuxhippy
This is simply wrong. The intel-driver team reported that even for 10x10 pixel areas blits are about 2x faster when done by the GPU, which is exactly in the reange which glyphs have.

However this was only for blits - where the destination is completly overwritten. Stuff like subpixel-AA'es fonts need to know whats "behind" the character they are drawing to compute the actual result which means the would have to read the area where the text should be rendered to from Video-RAM back into System-Ram and download it to the card again.
This is where the "software" slowness comes from.
Intel writes driver only for integrated GPUs where RAM<->RAM transfers are fast and there is no problem with moving blocks or operating on them. AFAIR from old news from Nvidia with discrete graphics there may be "bus access pattern" problem where all data must go from RAM to VRAM via bus. So cost of transmission must be calculated to decide if pixmap is big enough to be worth of setting all the processing chain.

Quote:
Originally Posted by Linuxhippy
Where do you know that cleartype is rendered "100%" in software?At least Sun was able to accalerate it using GLSL shaders when using their OpenGL pipeline in a cross-GPU manner and they did reach good results.
In Windows XP cleartype is done in software. Since WPF in Vista it is done in hardware (if GPU is DX9+).
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Old 03-09-08, 02:48 PM   #166
Linuxhippy
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by zbiggy
Intel writes driver only for integrated GPUs where RAM<->RAM transfers are fast and there is no problem with moving blocks or operating on them. AFAIR from old news from Nvidia with discrete graphics there may be "bus access pattern" problem where all data must go from RAM to VRAM via bus. So cost of transmission must be calculated to decide if pixmap is big enough to be worth of setting all the processing chain.
If the nvidia driver has to do readbacks (or even only pushes into VRAM which are usually cheaper) for small areas (as small as text areas) the software-rendering-readback-penality is even higher than the penality the intel-driver has to pay (in fact only changing some GART entries) - and even the intel driver is twice as fast when blitting a 10x10 pixmap in hardware (which includes seting up the blt engine). So you can just guess how much faster it is for the nvidia driver.

lg Clemens
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Old 03-10-08, 01:31 AM   #167
hyfans
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Default Re: Slow AA text rendering in KDE

Quote:
Originally Posted by evanlec
this glyph cache feature seems great and all, but im not sure if its having any effect...
is there a way to see whether it is enabled (i set the nvidia-settings -a Glyph_Cache=1 string), and if so whether its doing anything or not?

Thanks for paying attention to this btw

(8800 GTS with NVIDIA 171.06 driver, kernel 2.6.24.3)
in technical way, you can check by issuing this command:

nvidia-settings --query all | more

it will display all the options infos, including their attibutes.
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Old 03-10-08, 11:18 AM   #168
_john_i_
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Default Re: Slow AA text rendering in KDE

Even with the GlyphCache and InitialPixmapPlacement settings, scrolling a web site in konqueror on KDE4 is jerky on my 8600GT.

When my old geforce3 can do the same thing smooth as silk, something is very very wrong!
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