In short, the argument goes, the ability to write scheduling policies in BPF greatly lowers the difficulty of experimenting with new approaches to scheduling. Both our workloads and the systems they run on have become much more complex since the completely fair scheduler was introduced; experimentation is needed to develop scheduling algorithms that are suited to current systems. The BPF scheduling class allows that experimentation in a safe manner without even needing to reboot the test machine. BPF-written schedulers can also improve performance for niche workloads that may not be worth supporting in the mainline kernel and are much easier to deploy to a large fleet of systems.

source: https://lwn.net