Important Patches Land To Improve GNOME's Multi-Monitor Experience With High Refresh Rates
MR #1285 by Red Hat's Jonas Ådahl has finally landed. This is the material to allow scheduling of frames for each stage views separately. As summed up by Jonas:
This branch, while being quite large, has one major aim: split up the frame clock so that on the native backend each CRTC is driven by its own frame clock. In effect this means that e.g. a 144 Hz monitor and a 60 Hz monitor being active in the same session will not have to wait for each other to render. A window on the 144 Hz monitor will paint at 144 Hz, and mutter will composite to the monitor at 144 Hz, while a window on the 60 Hz monitor will paint at 60 Hz and mutter will composite to the monitor at 60 Hz.
This is very important for improving the multi-monitor experience with such configurations as up to now capping the refresh rate to match is a less than desirable experience. This work landed today in Mutter for September's release of GNOME 3.38. This next release is shaping up to be quite exciting with the plethora of optimizations to already land thus far. It is important to note that this multi-monitor improvement only benefits the GNOME Wayland session and not under X11.
Update: Jonas has now written a blog post as well outlining more of this work.