Proposed GNOME Patches Would Switch To Triple Buffering When The GPU Is Running Behind

The latest GNOME performance work being explored is effectively how to make the Intel graphics clock speed ramp up quicker when necessary. Canonical developer Daniel van Vugt is working on a set of patches for enabling triple buffering with Mutter when the GPU starts falling behind and that additional rendering work in turn should ramp up Intel GPUs to their optimal frequency in order to smooth out the performance.

Daniel has been working on various GNOME desktop optimizations focused primarily on Intel graphics and at 4K. He had been seeing the modern Intel "Iris" Gallium3D driver at times delivering lower performance than the classic "i965" driver. On investigation, he found that it wasn't due to the OpenGL driver per se but the iGPU was running in a lower clock/performance state.

With the GNOME Mutter triple buffering support, when needed it can hit "100% GPU utilization" and in turn getting the GPU frequency to scale up quickly. Double buffering for GNOME would remain the default as long as the presentation times are met.

The current triple buffering support is just working on the X.Org session but ultimately the plan is to also support Wayland.

More details on this work-in-progress functionality via this merge request.