Originally posted by agd5f
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RV350, compositing and horrible performance.
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Originally posted by agd5f View PostHow much vram does your card have? You may be running out of vram which causes thrashing in GPU memory manager (i.e., migrating stuff between gart and vram). Modern desktop compositors use a lot of memory.
Can i test vram pressure with 16 bbp or less output? If so, how would I change that?
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Originally posted by oliver View PostA whopping 64 MiB of vram. The display is 1440 x 1050 too!
Originally posted by oliver View PostCan i test vram pressure with 16 bbp or less output? If so, how would I change that?
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Originally posted by agd5f View PostThat's ~6MB per screen sized buffer at depth 24 (32 bpp). If you are using a GL compositor, you'll need a back buffer as well so that's 12 MB just for what you see on the screen.
You can change the depth of your root window by specifying Depth 16 in the screen section in your xorg.conf, but with a compositor, apps are allowed to use whatever depth they want, it will just all end up in 16bpp when it's composited onto the root window. Still it will save some memory at least for the root window and back buffer.
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Originally posted by oliver View PostI'll create an xorg.cofn just with the bit-depth in it hten; if thats possible. Anyway, you are saying 12 MiB for the 'plain' empty background. Which still leaves me with about 52 MiB of vram. Is there an easy way to check if it's lack of vram? You think a plain gnome 3 shell uses that much ram?
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Originally posted by oliver View PostA whopping 64 MiB of vram. The display is 1440 x 1050 too!
Can i test vram pressure with 16 bbp or less output? If so, how would I change that?
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Also, as noted previously in this thread, it's probably worth adjusting the cpu governor you are using to see if that helps. See https://bugs.freedesktop.org/show_bug.cgi?id=51787#c6 for an idea of how cpu performance can affect GPU performance.
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I had turned on the performance governor yesterday, and that didn't really make a difference.
I put it on 1024x768 and wow what a differnce that makes. It does seem actually to be pretty smooth. Not perfect, but pretty good. I can't say I notice a difference with 800x600, but that resolution is really hard to work with. 1280x960 appears to be choppy-ish again. Not hugly bad, but quite noticeable.
So yeah, problem seems to be in that direction. But can it be solved? I guess using gnome-fallback is out of the question So any/all compositers out of the question? I suppose E17 can still work nicely on old hardware
How much vram is one expected to have? "Any modern video card" doesn't really tell you anything ...
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We probably need a good VRAM defragmentation tool... perhaps combined with some texture prediction engine.... that would solve your problem. Basically every window in compositor is a texture, and every texture has different block size. If the VRAM is limited, allocated/deallocated textures will make "holes" in VRAM in the process - similar to fragmentation of hard disk, and will hinder larger textures to be fit in video memory. So they will be allocated in system memory instead. Leading to reduced performance.
This is exactly like machine whose software fits into RAM compared to machine with low RAM and constantly swapping from hard drive.
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Well I also noticed that AGP mode was forced to 1. (Yes, AGP remember? ) This bug report mentions it and fixes it: https://bugs.launchpad.net/ubuntu/+s...ux/+bug/544988
Before the AGP change, this is what i found in xorg.log
[ 11.498] (II) RADEON(0): mem size init: gart size :fdff000 vram size: s:4000000 visible:3a1c000
does look like 64 MiB for vram?
[ 11.499] (II) RADEON(0): [DRI2] DRI driver: r300
[ 11.499] (II) RADEON(0): [DRI2] VDPAU driver: r300
why not r300g? or this just a nameing thing
[ 11.499] (II) RADEON(0): Front buffer size: 5808K
[ 11.499] (II) RADEON(0): VRAM usage limit set to 48297K
and later:
[ 42.599] (II) RADEON(0): VRAM usage limit set to 50760K
After reboot btw, those limits remain. So why a limit lower then available VRAM?
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