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aminal Apprentice
Joined: 17 Mar 2004 Posts: 170 Location: Baltimore, MD
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Posted: Mon Mar 29, 2004 10:52 pm Post subject: NvAGP vs AGPGART |
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hey guys - quick question;
i was going through dmesg and I noticed an alert that said 'cannot load nvagp agpgart is already loaded!' now, i know I compiled agpgart as a module, but I also chose agp support for the via chipset (which is what I have on the mobo) , which I compiled in. Now, when I do an lsmod, via_agp and agpgart are loaded, with agpgart being used by via_agp. agpgart isn't in my autoload file, so obviously it's being loaded by via_agp.
My question is: do I go back and change via agp support to a mudule as well and recompile? Is it safe? How big is the performance difference between agpgart and NvAGP anyway?
Thanks a lot. |
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aminal Apprentice
Joined: 17 Mar 2004 Posts: 170 Location: Baltimore, MD
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Posted: Tue Mar 30, 2004 12:22 am Post subject: |
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Nobody knows, huh? |
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mike4148 l33t
Joined: 09 Sep 2003 Posts: 641
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Posted: Tue Mar 30, 2004 12:41 am Post subject: |
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The performance difference varies between systems.
If I were you, here's what I would do:
1. Run a heavy-duty benchmark (i.e., not glxgears; commercial games/demos work well) under X with NvAGP set to "2" (and the agpgart and via_agp modules loaded). Be sure to run it a few times.
2. Build your kernel with NO agpgart support at all; hotplug will autoload your agpgart modules if they exist. Needless to say, boot into your newly-built kernel.
3. Run the same benchmark with NvAGP set to "1". Compare and contrast, and decide which one you want to use.
If you don't really care, I'd use nVidia's AGP, unless it did not support your chipset. In which case, I'd use agpgart. I'm assuming that nVidia's black box AGP code was tuned for their cards. |
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aminal Apprentice
Joined: 17 Mar 2004 Posts: 170 Location: Baltimore, MD
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Posted: Tue Mar 30, 2004 1:06 am Post subject: |
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mike4148 wrote: | The performance difference varies between systems.
If I were you, here's what I would do:
1. Run a heavy-duty benchmark (i.e., not glxgears; commercial games/demos work well) under X with NvAGP set to "2" (and the agpgart and via_agp modules loaded). Be sure to run it a few times.
2. Build your kernel with NO agpgart support at all; hotplug will autoload your agpgart modules if they exist. Needless to say, boot into your newly-built kernel.
3. Run the same benchmark with NvAGP set to "1". Compare and contrast, and decide which one you want to use.
If you don't really care, I'd use nVidia's AGP, unless it did not support your chipset. In which case, I'd use agpgart. I'm assuming that nVidia's black box AGP code was tuned for their cards. |
Sounds good. But you also answered another question I was going to ask...I think. You're saying hotplug is what loads the via_agp and in turn the agpgart modules? |
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justanothergentoofanatic Guru
Joined: 29 Feb 2004 Posts: 337
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Posted: Tue Mar 30, 2004 3:55 am Post subject: |
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The kernel has a built-in module autoloader that will load modules as needed. Hotplug is not necessary to load the AGP modules.
To reiterate mike's comments: If you want to use the nVidia AGP driver, you'll have to completely disable both DRI and AGPGART in the kernel. Compiling them as modules and unloading the modules is not sufficent.
In my experience, the nVidia driver is much more stable than the xfree one. However, I have an nforce motherboard.
-Mike |
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Suicidal l33t
Joined: 30 Jul 2003 Posts: 959 Location: /dev/null
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Posted: Tue Mar 30, 2004 4:01 am Post subject: |
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I have an old i815 board with a GF ti 200 and a work computer wit an i850 they both perform much faster via Nvidia's agp support vs xfree's.
I have used glxgears, games-action/armagetron, games-fps/ut2003 The nvidia drivers are at least 30% faster in my case. |
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