The Linux kernel's scheduler is one of its most critical components, determining which tasks run on which CPUs and for how long.
But in today's complex computing environments, the default Linux scheduler doesn't always provide optimal performance for specialized workloads. This is where sched_ext (SCX) comes in – a framework that allows implementing custom CPU schedulers in BPF (Berkeley Packet Filter) and loading them dynamically. In this technical analysis.
I'll examine the architecture and implementation of SCX schedulers, with a particular focus on scx_rustland and scx_bpflandand, compared to traditional schedulers.
What is sched_ext?
Sched_ext
Linux kernel 6.12 introduced sched_ext (“extensible scheduler”) as a new scheduling class that allows pluggable CPU schedulers via eBPF