RADV Lands VK_EXT_subgroup_size_control For Exposing Wave32 On Navi/GFX10

[phoronix]

Phoronix: RADV Lands VK_EXT_subgroup_size_control For Exposing Wave32 On Navi/GFX10

Valve open-source developer Samuel Pitoiset has landed his work enabling the Vulkan VK_EXT_subgroup_size_control extension that for GFX10/Navi is being used to expose Wave32 capabilities...

http://www.phoronix.com/scan.php?page=news_item&px=RADV-Wave32-Subgroup-Size

[shmerl]

So something like dxvk would need to explicitly make use of it, to benefit from wave32?

Aco wave32 is currently work in progress: https://gitlab.freedesktop.org/Venem...co-navi-wave32

[mifritscher]

I don't think Wave32 is always better, so it should be enabled/used by the software.

[shmerl]

Also, does it only affect compute shaders, or other shaders can benefit from wave32 too?

[Venemo]

So something like dxvk would need to explicitly make use of it, to benefit from wave32?

Wave32 is not currently the default, but you can opt to use it with a couple of environment variables. It doesn't yield a significant enough benefit, and is not always better, as far as I've played around with it.

Aco wave32 is currently work in progress: https://gitlab.freedesktop.org/Venem...co-navi-wave32

Please don't use that branch yet, that is some pretty old code there and it has a number of unsolved problems. You will hear from it when it's ready.

[shmerl]

Please don't use that branch yet, that is some pretty old code there and it has a number of unsolved problems. You will hear from it when it's ready.

I didn't use it yet, just saw that it's there