Intel has rolled out a new Linux graphics driver patch for the Arc Alchemist GPUs, drastically improving ray-tracing performance in games leveraging the Vulkan API. As reported by Phoronix, the patch rolled out the other day was aimed at improving ray-tracing performance, yielding “like a 100x (not joking) improvement“. And the best part? A single line of code brought about this massive boost.
Intel’s veteran Linux graphics engineer Lionel Landwelin opened this merge request on 21st July after discovering the critical optimization which was added to Mesa 22.2. This one line of code essentially ensures the scratch memory for Vulkan ray-tracing use gets allocated to local memory (discrete memory of the Arc GPUs). Up until now, the ray-tracing scratch memory didn’t have any allocation flags set, resulting in it being allocated in the main system memory, leading to a severe overhead.
It’s a fortunate co-incidence that this bug was caught before the widespread rollout of the Arc GPUs. Mesa 22.2 is set to be branched soon and all its optimizations and additions are slated to land by the end of August.