Intel Iris Gallium3D Picks Up More Game Performance Optimizations For Mesa 19.1

There is just one week to go until the Mesa 19.1 feature freeze and branching for this next quarterly feature update to these open-source OpenGL/Vulkan Linux drivers. Notable this round is the introduction of the Intel "Iris" Gallium3D driver for supporting Broadwell graphics and newer atop this next-gen OpenGL driver ahead of next year's Xe Graphics dGPU launch. With days to go until the Mesa 19.1 feature freeze, more performance optimizations have landed.

Kenneth Graunke of the Intel Open-Source Technology Center who has led the Iris Gallium3D driver development for more than the past year pushed a number of notable improvements into Mesa Git today.

iris: Track valid data range and infer unsynchronized mappings - On Skylake graphics this improves the FPS average for games like DiRT Rally, Bioshock Infinite, and Shadow of Mordor by 2~7% and the max FPS by as much as 9~20%.

iris: Replace buffer backing storage and rebind to update addresses - This commit is even more noteworthy as it improves the performance for the same set of OpenGL games by 22~27% on average and in the case of Shadow of Mordor the peak FPS improves by as much as 83%.

With this commit and others are also some rendering fixes.

Overall the Iris driver is looking to be in great shape for Mesa 19.1 with its inaugural debut albeit not yet enabled by default over the mature i965 driver. I'll have more i965 vs. Iris Gallium3D OpenGL Linux gaming benchmarks on Phoronix shortly. Last week I posted some fresh numbers at the time but given the Mesa commits since then, Mesa 19.1 with Iris might now be able to come out well in front of i965 at least for a subset of the Linux GL games.