AMD ACO Begins Using Navi NGG For Tessellation + Vertex Shaders

The AMD "ACO" compiler backed by Valve for offering a faster shader compiler back-end than AMDGPU LLVM for the RADV open-source Radeon Vulkan driver has begun making use of Navi's NGG "Next-Gen Geometry" hardware.

It has been a slow path for the open-source OpenGL/Vulkan drivers to make use of NGG as found with the Navi/GFX10 hardware (sans Navi 14 being borked). There have been bugs to deal with and other obstacles in supporting this engine designed to offer faster geometry performance.

Up to now NGG was disabled by default when using the ACO back-end while now it's enabled for vertex shaders and tessellation shaders. Still to be supported by ACO is the NGG Stream-Out capabilities.

This NGG vertex and tessellation eval shader support comes via this merge request that had been in the works for the past two months but is now in good shape for Mesa 20.1.

We'll have up some fresh RADV+ACO benchmarks as the Mesa 20.1 feature freeze approaches later this month.