Intel Wires In EGL Context Priority Support For Their Mesa Driver

With the Mesa 17.3 branching being imminent, it's a very busy week for open-source graphics driver developers from all the major organizations as they try to land their last-minute improvements for this next quarterly and final Mesa stable update for 2017.

Chris Wilson of Intel today landed the code implementing EGL_IMG_context_priority within core Mesa EGL and then the necessary bits for their i965 OpenGL driver across multiple commits.

EGL_IMG_context_priority is a means of allowing EGL contexts to specify priority hints. These hints are for allowing games/applications to allow for higher priority access to the GPU, but not necessarily honored, so there's also a query so the application can find out what priority level it ended up being assigned. More details about this context priority extension created by Imagination Tech can be found via the Khronos Registry.

This goes in-step with Intel's latest DRM changes for Linux 4.15 where their kernel driver now supports user-defined priorities within their scheduler.

While at least not yet using EGL_IMG_context_priority in RadeonSI, coming to the AMDGPU DRM driver too for Linux 4.15 is priority scheduling support. On the AMDGPU side, the code was worked on by Valve with their use-case of ensuring VR games/compositor have high priority access to the GPU for ensuring sufficient performance to avoid the possibility of motion sickness or related woes in the virtual reality space when not being able to render frames as expected.