Re: How to disable slow agpgart in kernel config?

From: Marcus Hartig
Date: Sat Feb 12 2005 - 13:17:28 EST


Terence Ripperda wrote:

> I wouldn't expect even falling back to pci dma would have this big of an
> impact on 2d performance, but perhaps there's enough bus activity for
> this to happen. Marcus, can you verify that you're actually using
> agpgart in that situation? do you possibly have our XF86Config option
> set to nvagp only? (with IOMMU compiled in or agpgart loaded, our driver
> won't allow nvagp) you can verify whether agp is enabled with this
> command when our driver is loaded and X is started up:

No, IOMMU is now off, too. And I have always used nv_agp with:

Option "NvAgp" "1"

If the nvidia driver detects the kernel agpgart, it doesn't load nv_agp with a big message in the kernel log.

I've just short tested it again:

Doom3 with medium standard settings in 800x600@24bit:

agpgart: 58,1 frames
nv_agp: 63,1 frames

Its a lot in Doom3.

(Simple) 2D test 1280x1024@24bit with x11perf --> http://www.marcush.de/bench/

Same gcc, xorg 6.8.2, 2.6.11-rc3-bk8 kernel, patched (minion.de) 6629 nvidia drivers to run with newer 2.6.11-rcX kernel,... here was only nv_agp and agpgart the difference. In the past without an patched driver the same difference.

And again using agpgart with GNOME under X and moving this thunderbird mail window or other bigger ones like mozille or firefox over an gnome-terminal pulls/draws a ca. 5cm shadow like field slowly after the main window. It seems so not fast enough writing to the screen, when moving. With nv_agp its really faster and you do not see this.

Bad english... I know. ;)

Greetings,
Marcus
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