RADV LBVH Ray-Tracing Code Lands In Mesa 22.2

The Mesa Radeon Vulkan driver "RADV" LBVH support has landed for boosting the Vulkan ray-tracing potential for this open-source driver. The LBVH patch series is what I reported on earlier this month for at least one workload going from around 13 to 250 FPS boost.

LBVH in this context is for Linear Bounding Volume Hierarchy. The RADV pull request by Konstantin Seurer makes use of LBVH for building acceleration structures. The RADV LBVH patches is what yielded going from ~13 to ~250 FPS for RADV with the GravityMark Vulkan RT benchmark. The performance in GravityMark is hugely better butfor other Vulkan ray-tracing software your mileage may vary with no impact for some tests.

As explained in the MR, "The 'new' bvh building code uses a combination of [NVIDIA reference code] and [Google Fuchsia's graphics radix sort code] to sort the nodes along a space filling curve before creating the internal nodes."

The LBVH merge request was merged a few minutes ago making this RADV ray-tracing improvement part of next quarter's Mesa 22.2 release.