The window manager Mutter's code, being developed as part of the GNOME 3.34 development cycle, initially supports a new transactional (atomic) API
(Atomic Kernel Mode Setting) for switching video modes, which allows checking the correctness of parameters before actually changing the hardware state at once and reverting the change if necessary.
From a practical standpoint, support for the new API is the first step toward transitioning Mutter to a multithreaded model, where the code interacting with the video subsystem, components related to OpenGL, and the main event processing loop of GLib run in separate threads. This will enable the parallelization of rendering operations on multi-core systems. The release of GNOME 3.34 is scheduled for September 11.
Source: opennet.ru
