Post Syndicated from original https://lwn.net/Articles/899303/

The CPU scheduler’s job has never been easy; it must find a way to allocate
CPU time to all tasks in the system that is fair, allows all tasks to
progress, and maximizes the throughput of the system as a whole. More
recently, it has been called upon to satisfy another constraint: minimizing
the system’s energy consumption. There is currently a
patch set in circulation, posted by Vincent Donnefort with work from
Dietmar Eggemann as well, that changes how this constraint is met. The
actual change is small, but it illustrates how hard it can be to get the
needed heuristics right.