Valve has long supported the idea of improving the capabilities of Linux when it comes to PC gaming. Its recent efforts began with the ill-fated Steam Machine, which ran on the Linux-based SteamOS. It also made efforts to improve the open-source Windows compatibility layer Wine.

The problem with Wine is that it struggles with more hardware-demanding programs. Valve attacked this challenge by launching a beta version of Steam Play that includes Proton — a game-friendly build of Wine. While this did help some, there were still many issues with performance.

In the most recent build of Proton's patch notes, Valve proposes changes to the Linux kernel to overcome problems it saw while trying to run some games.

To begin with, it has an experimental replacement for esync called fsync which provides "support for futex-based in-process synchronization primitives" and reduces CPU usage more than esync. However, because it requires the use of the kernel's eventfd() function, it needs modifications to the Linux kernel to work correctly.