DRM Buddy & AMDGPU Wired Up For Clear Page Tracking In Linux 6.10

[phoronix]

Phoronix: DRM Buddy & AMDGPU Wired Up For Clear Page Tracking In Linux 6.10

Sent in to DRM-Next as part of last week's drm-misc-next changes is implementing support for tracking cleared free memory and is initially wired up for the AMDGPU kernel graphics driver...

https://www.phoronix.com/news/DRM-Buddy-Clear-Page-Tracking

[Kjell]

This patch mitigates stuttering introduced by 6.2 kernel thus massively helping games like Cyberpunk 2077

I'm glad they left the issue report open since the performance of this patchset is still not at its fullest potential in comparison to the original performance

https://gitlab.freedesktop.org/mesa/mesa/-/issues/9189#note_2371899

[Kjell]

For those curious about the cause of this regression:

The original commit actually fixed a rather bad bug. The stuttering is just the immediate effect of having the ordering now correctly done. So we absolutely can't revert that in any way possible.

[...] the kernel driver didn't fully blocked out access to freshly allocated memory which is still cleared by the hardware.

So what could potentially happen without that patch is screen corruption where parts of the rendering are just overwritten by black.

memset() is by far the absolute worst option.

https://gitlab.freedesktop.org/mesa/...9#note_1988302

TLDR: The new approach of cleaning the memory in kernel improves stability and has the potential to enhance game performance.

[shmerl]

Too bad it wasn't added in 6.9.

[bosslog]

Will this (potentially) reduce VRAM usage in games when using amdgpu?

[shmerl]

Will this (potentially) reduce VRAM usage in games when using amdgpu?

It will reduce fragmentation, so may be will allow more optimal usage. I doubt it can decrease usage.