Toward better CPU load estimation

Linux doesn't include the entire windowing stack in the kernel so it cannot apply that kind of heuristic. There is a user space solution though - ulatencyd.

Android does exactly that. (Called foreground processes.) It breaks things that require steady throughput and low latency, like media handling. Everywhere where you need a wake-up estimate and are using a dumb controller to get runtime, you get immense noise.

It is also highly unnecessary. If you have preemptible kernel, standard task start handling puts new tasks on top of their parents tree of tasks to be scheduled. (Tunable in sysfs.) If there is no restart, boost shouldn't be necessary on a preemptible kernel anyway, especially rt enabled ones, as lock holders on input will get woken up.

About the only place where it is useful is in boosting cpu clocks. This is also where it breaks timings the most.

As far as I know Linux uses a different heuristic that achieves similar results.

A process that sometimes, but not all the time, uses a lot of cpu time is considered interactive and prioritized accordingly.

You have to enable the SCHED_UTILEST flag when compiling the kernel. Most end-users don't compile their own kernels, as doing so requires a very large and time-consuming amount of configuration, but you can if you want (might want to start with your distribution's configuration as a base).