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AMD APU, Ubuntu - Texture memory always detected too low
http://sldev.free.fr/forum/viewtopic.php?f=6&t=2150		 Page 1 of 1
Author:  Jenna Huntsman [ 2021-03-27 13:34:50 ]
Post subject:  AMD APU, Ubuntu - Texture memory always detected too low
Hey Henri,

I recently installed Ubuntu on my laptop (for a couple reasons, but mainly to get better SL performance on it as that's the only thing I use it for these days) - SL runs pretty well on it, averaging around 30 fps, but I have an annoying issue wherein I suffer from extreme texture thrashing due to the detected VRAM amount often being reported as approx. 256MB (This also isn't consistent, have seen it go as low as 64!! --In a laptop with 16GB RAM, APUs don't have VRAM and instead have system RAM allocated for use as VRAM, so it doesn't ever have a fixed amount, the idea being it will use as much as it needs), so it seems like whichever method is being used to detect the available VRAM amount doesn't play nice with APUs.

I've worked out I can get around the problem by using the TextureMemory debug setting and manually set it to 2056, but this doesn't persist on reboot but does seem to solve the thrashing issue for the duration of that session.

Logs attached!

Attachments:
CoolVLViewer.zip [20.28 KiB]
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Author:  Henri Beauchamp [ 2021-03-27 13:51:15 ]
Post subject:  Re: AMD APU, Ubuntu - Texture memory always detected too low
You are not using the right approach: there is an LL_VRAM_MB environment variable override for this purpose. Simply add it to your configuration file. For a system-wide setting (which is recommended in your case, since anyone using the viewer on your system will have the same issue), type in a terminal, as root:
Code:
echo "export LL_VRAM_MB=2048" >>/etc/cool_vl_viewer.conf


It is normal that the viewer cannot detect the available VRAM in all cases (and in particular with iGPUs/APUs: they do not have any VRAM and use the CPU RAM as such instead...), since it relies on X11 logs (not available on a Wayland system) and/or on proprietary NVIDIA and AMD methods of getting the GPU VRAM amount. In your log, you can see:
Code:
2021-03-27T13:18:53Z INFO: x11_detect_vram_kb: Looking in /var/log/Xorg.0.log for VRAM info...
2021-03-27T13:18:53Z WARNING: x11_detect_vram_kb: VRAM amount detection failed. You could use the LL_VRAM_MB environment variable to specify it.


Also see the cool_vl_viewer.conf file in the viewer installation directory for more options that you can set with environment variables.
Author:  Jenna Huntsman [ 2021-03-27 14:10:51 ]
Post subject:  Re: AMD APU, Ubuntu - Texture memory always detected too low
Henri Beauchamp wrote:
You are not using the right approach: there is an LL_VRAM_MB environment variable override for this purpose. Simply add it to your configuration file. For a system-wide setting (which is recommended in your case, since anyone using the viewer on your system will have the same issue), type in a terminal, as root:
Code:
echo "export LL_VRAM_MB=2048" >>/etc/cool_vl_viewer.conf


It is normal that the viewer cannot detect the available VRAM in all cases (and in particular with iGPUs/APUs: they do not have any VRAM and use the CPU RAM as such instead...), since it relies on X11 logs (not available on a Wayland system) and/or on proprietary NVIDIA and AMD methods of getting the GPU VRAM amount. In your log, you can see:
Code:
2021-03-27T13:18:53Z INFO: x11_detect_vram_kb: Looking in /var/log/Xorg.0.log for VRAM info...
2021-03-27T13:18:53Z WARNING: x11_detect_vram_kb: VRAM amount detection failed. You could use the LL_VRAM_MB environment variable to specify it.


Also see the cool_vl_viewer.conf file in the viewer installation directory for more options that you can set with environment variables.


Awesome, thanks Henri!
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