The State Of RADV's Vulkan Mesh Shading Support

Yesterday on the first day of the X.Org Developers' Conference (XDC 2022), Timur Kristóf of Valve's open-source Linux GPU driver team presented on the Vulkan mesh shader support being worked on for RADV.

Introduced at the start of September with Vulkan 1.3.226 brought VK_EXT_mesh_shader as finally having a cross-vendor mesh shader extension for the Vulkan API. The VK_EXT_mesh_shader extension is a new mechanism to let applications generate collections of geometric primitives via programmable mesh shading. Vulkan mesh shaders are an alternative to the existing programmable primitive shading pipeline.

This mesh shader support is one of the most notable additions to the Vulkan API for 2022 and was quickly supported by RADV thanks to Timur having been working on earlier support with NVIDIA's mesh shader vendor extension. Supporting the extension though has been rather a challenging headache. RADV also isn't exposing the mesh shader functionality by default yet until Linux 6.1 is out there with the AMDGPU gang submit support.

For those wanting to learn more about the Vulkan mesh shader functionality particularly in the context of Mesa/RADV, Timur's presentation from XDC 2022 is embedded below and there is also the PDF slide deck.