Intel Linux Graphics Stack Gets Another Speed Boost - Helping Civilization VI By ~18%

Intel's open-source Linux graphics driver crew has been on an exciting spree lately of not only punctually enabling new hardware support but also pushing some big performance improvements for new and existing generations of graphics hardware. Today another performance achievement was unlocked.

Kenneth Graunke who led the development of their new Gallium3D OpenGL driver discovered an optimization today that not only benefits that "iris" driver but also the i965 classic OpenGL driver and their ANV Vulkan driver. The optimization is to stop redirecting the state cache to the command stream command buffer cache section. By looking through their hardware documentation and comparing the behavior to the Intel Windows driver, this optimization was uncovered.

The change comes down to just deleting the 23 lines of code between the two OpenGL and Vulkan drivers. In doing so, the performance of Civilization VI on Linux with Intel graphics improved by 18%, the Manhattan GL benchmark improved by 6%, and the Car Chase demo by 2%. It will be interesting to see what other games/workloads are helped by this change.

This change was made today in Mesa 19.3 Git that will be released next quarter and at least as of commit-time wasn't marked for back-porting to Mesa 19.2.