Making a GDS Allocation for NGG

[Jin, Jian-Rong]

Hi Jakub。
Both KMD and LLPC are not ready to support NGG for gfx9. We are going to support NGG in amdvlk for next generation GPU.

Thanks
Jian-Rong JIN

-----Original Message-----
From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> On Behalf Of Jakub Okoński
Sent: 2018年8月14日 21:31
To: amd-gfx at lists.freedesktop.org
Subject: Making a GDS Allocation for NGG

Hi folks,

I was trying to play around with NGG on Vega using the open source AMDVLK stack.
After fetching all the code, I disabled an override in PAL, under gfx9SettingsLoader.cpp that disables the NGG setting. I've put a new option in my
amdPalSettings.cfg: `NggMode,7` and that was enough to enable it.

When I ran a small vulkan application, it crashed with a "Not implemented" error in Pal::Linux::Device::AllocateGds. The comment there says:

    // TODO: implement it once amdgpu is ready.

I couldn't find anything specific to GDS allocation in upstream kernel, so I looked at agd5f/amd-staging-drm-next and found some code related to AMDGPU_GEM_DOMAIN_GDS and allocating a bo object. This is in amdgpu_gem_create_ioctl, so I think it's accessible to userspace, with a small change in libdrm, probably.

Is this what is needed to make a GDS allocation that NGG would accept, or is it unrelated? Do you know if there are any other blockers for NGG besides this?

Regards,
Jakub
_______________________________________________
amd-gfx mailing list
amd-gfx at lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx