RadeonSI Gallium3D Driver Adds Navi Wave32 Support

One of the new features to the RDNA architecture with Navi is support for single cycle issue Wave32 execution on SIMD32. Up to now the RadeonSI code was using just Wave64 but now there is support in this AMD open-source Linux OpenGL driver for Wave32.

Well known AMD open-source developer Marek Olšák landed this Wave32 support on Friday for the RadeonSI driver. The Wave32 support landed over several commits to Mesa 19.2-devel and is enabled for vertex, geometry, and tessellation shaders. Wave32 isn't enabled for pixel shaders but rather Wave64. Additionally, Wave32 isn't yet enabled for compute shaders due to Piglit OpenGL test case failures.

This Wave32 support though should help the performance at least for the shaders where it's turned on.

In addition to the Wave32 Navi support landing in RadeonSI, there was also ARB_post_depth_coverage for GFX10/Navi turned on, SDMA support is now enabled, and other Navi bits that reached Mesa 19.2 Git on Friday.

I'll have out new Radeon RX 5700/5700XT benchmarks next week now that the Linux open-source driver support for these new AMD graphics processors is stabilizing quite well just a few weeks after launch.