Linux Plumbers Conference 2024

Sched-Ext: The BPF extensible scheduler class

Not scheduled

20m

LPC Microconference Proposals

Speakers

Andrea Righi (NVIDIA) Changwoo Min (Igalia) David Vernet (Meta)Mr Giovanni Gherdovich (SUSE)Mrs Himadri Chhaya-Shailesh (Inria-Paris)Mr Peter Jung (CachyOS)Mr Piotr Górski (CachyOS)

Description

Overview

sched_ext is a Linux kernel feature which enables implementing host-wide, safe kernel thread schedulers in BPF, and dynamically loading them at runtime. sched_ext enables safe and rapid iterations of scheduler implementations, thus radically widening the scope of scheduling strategies that can be experimented with and deployed, even in massive and complex production environments.

sched_ext was first sent to the upstream list as an RFC patch set back in November 2022. Since then, the project has evolved a great deal, both technically, as well as in the significant growth of the community of sched_ext users and contributors.

Discussions

The following are the main topics that will be discussed during the MC:

• An update on the current status of sched_ext, initiating discussions about potential future directions, and the growth of the community.
• The componentization of the scheduler using a library-oriented approach to minimize code duplication among the scx schedulers.
• Defining a set of APIs for user-space scheduling, including Rust schedulers and Rust/C hybrid schedulers.
• Distro integration: addressing challenges and open issues related to shipping sched_ext and scx-based schedulers in Linux distributions.
• Practical applications of sched_ext: exploring how sched_ext can be utilized and its benefits in real production environments (e.g., SteamDeck, Meta).
• The use of sched_ext in virtualized and para-virtualized environments.

Logistics notes

• This is the first time we've proposed a sched_ext MC, so we have no results and accomplishments to discuss from prior meetings
• We've discussed the possibility of combining with either the sched or sched-RT microconferences with the authors of those MCs, and we all agree that there are already too many topics to combine the MCs