Intel NIR I/O Vectorization Ported From The AMD ACO Back-End - ~10% Performance Boost

Lead Intel "ANV" open-source Vulkan driver developer Jason Ekstrand has ported an optimization from the Valve-backed AMD "ACO" compiler over to the NIR code-base for delivering some sizable performance improvements.

Ekstrand has enabled an I/O vectorization pass for NIR that is originally based on the ACO code for the Mesa Radeon Vulkan driver. This vectorization pass is enabled for UBOs, SSBOs, global memory, and SLM.

This helps the performance in OpenGL and Vulkan games like Deus Ex: Mankind Divided, Doom, Shadow of Mordor, DiRT Showdown, Batman titles with DXVK, and others. Besides more efficient shaders, the game frame-rates generally improved by about 10%.

The merge request was opened this weekend but not yet merged, but hopefully will be landing soon in Mesa 20.1-devel as another step forward for Intel's OpenGL and Vulkan driver performance on Linux. Benchmarks of Mesa 20.1-devel soon.