[soulbadguy]

The scheduler doesn't need to know which process is associated with the currently active windows.

Simple heuristics can get you which to "reasonably" guesstimate which process are interactive and which aren't. For example, every X and descendant, or everything waiting on keyboard/controller or any other input.

I think the linux kernel historically did not want to prioritize interactive processes like windows and macos does.

The other thing is of course to reduce the CPU quanta, trading latency for throughput. I think most modern distribution do ship with better quanta for smooth GUI/desktop behavior.