Mesh/Task Shader Queries Land For RADV With RDNA2, RDNA3 Support On The Way

Thanks to prolific RADV driver developer Samuel Pitoiset of Valve's Linux graphics team, mesh/task shader queries have landed for GFX10.3 (RDNA2) with the in-development Mesa 24.0 while support for GFX11 (RDNA3) graphics cards is on the way.

This latest work thanks to Valve's stellar open-source contributions allows for "meshShaderQueries" to be exposed for RDNA2 graphics processors. Though for RDNA2 the meshShaderQueries support needs to be emulated while the RDNA3 support under review makes use of native hardware capabilities.

This merge that landed last week wires up mesh/task shader queries for RDNA2 hardware like the Steam Deck. Meanwhile the RDNA3 support is being reviewed via this merge. Though on the RDNA3 front currently Samuel Pitoiset is battling issues with the new geometry shader fast launch mode is currently disabled fur performance reasons and a concurrent task shader GPU hang is making it hard to properly test this new code.

He ended that merge request for RDNA3 mesh/task shader queries with:

"At least, the code is there and it will be fixed if needed (ie. there might be sync issues as usual with queries) when the above issues are also fixed."

There's still a month and a half to go before the Mesa 24.0 feature freeze so there is time to see this code all fixed up as well as seeing whatever other features Valve may have in store for this next quarterly feature release of these open-source 3D drivers.

Another RADV change that slipped on my TODO list for writing about that came by way of Bas Nieuwenhuizen is the compute DGC pre-processing support to help reduce overhead to less syncs.