KDE Screen Querying Is Much Faster On Wayland

KDE's Sebastian Kügler has been blogging about KDE Plasma on Wayland lately and some of the ongoing work. Today he shared some interesting performance numbers.

These numbers aren't about the performance of running your favorite game or app on Wayland, but rather the time difference it takes in querying monitor information under X11 and Wayland with the different back-ends. This is important for efficient screen management on KDE and is also important as it affects the start-up time of the KDE Plasma shell.

What did Kügler find? He wrote in today's post, "My results show a speedup of between 2 and 2.5 times when querying screen information on X11 and on wayland, wayland being much faster here. The qscreen and xrandr backends perform pretty similar, they’re both going through XCB. That checks out. The difference between wayland and xrandr/qscreen can then be attributed to either the wayland protocol or its implementation in KWayland being much faster than the corresponding XCB implementations." Loading the back-end in-process also makes it ten times faster.