Blender Git Commit Log

Cycles Denoising: Disable local (aka shared) memory on OpenCL

On GPU architectures, storing the design row in local memory improves performance due to lower global memory bandwidth requirements.
However, if the GPU doesn't have enough local memory available, occupancy suffers which makes it even slower than the global memory version.

On CUDA, the amount of available local memory (shared memory in CUDA terminology) can be controlled, but that's not possible on OpenCL. So, to avoid a huge performance hit when the local memory isn't enough, it's disabled on OpenCL.