Radeon RADV Vulkan Driver Adds Navi Wave32 Support For Compute Shaders

Thanks to Valve's open-source driver developer Samuel Pitoiset, there is now experimental support for using Wave32 support on Navi graphics cards for compute shaders.

Navi/RDNA brings support for single-cycle issue Wave32 execution as an alternative to Wave64 for better efficiency. Just over a week ago the initial patches landed adding Wave32 support to RadeonSI for their OpenGL driver while now Samuel has tackled the initial implementation in the RADV driver.

This Wave32 support is for compute shaders and as of writing isn't enabled by default. The code is queued into Mesa 19.2-devel Git but requires setting the RADV_PERFTEST=cswave32 environment variable for enabling the support on new Radeon RX 5700 / RX 5700 XT graphics cards. Wave32 currently isn't hooked in for any other shader types.

Samuel also submitted a number of fixes today for this Navi code in RADV via radv/gfx10.

Mesa 19.2 feature development is ending next week while fixes are still permitted to land. Mesa 19.2.0 should debut as stable in late August or early September while feature development then shifts to Mesa 19.3 for debut at the end of November.