scx_wd40

An experimental fork of the scx_rusty scheduler that uses BPF arenas to simplify scheduler development. Found in the main sched_ext repository. Read more about sched_ext.

Overview

A multi-domain, BPF / user space hybrid scheduler. The BPF portion of the scheduler does a simple round robin in each domain, and the user space portion (written in Rust) calculates the load factor of each domain, and informs BPF of how tasks should be load balanced accordingly.

Goals

This scheduler ultimately aims to demonstrate how to build modular BPF schedulers to enable easy code reuse between scheduler codebases. The main way of achieving this is through the use of BPF arenas that make it possible to directly share memory between the userspace and kernel scheduler components. This in turn lets us offload most of the complexity of the scheduler to userspace. Userspace components can be more easily combined, as opposed to scheduler BPF methods that are often mutually exclusive.

Production Ready?

No. This scheduler heavily uses BPF arenas and as such routinely requires a bleeding-edge kernel toolchain to even run and verify.