Overview

scx_rust_scheduler is a fully functional FIFO scheduler for the Linux kernel that operates in user-space and it is 100% implemented in Rust.

It is based on scx_rustland_core, a framework that is specifically designed to simplify the creation of user-space schedulers, leveraging the Linux kernel's sched_ext feature and BPF.

The scheduler is intended to serve as a basic template for developers who want to experiment with more advanced scheduling policies without having to directly engage with low-level kernel internals.

Requirements

In order to run this scheduler you need a kernel that supports sched_ext (CONFIG_SCHED_CLASS_EXT=y).

You also need the following binaries/packages in order to build the scheduler:

• cargo
• rustc
• bindgen
• bpftool
• libbpf

CachyOS

CachyOS ships a sched_ext kernel by default, so you only need to install the following user-space packages:

$ sudo pacman -S bpf libbpf rust clang pkgconf

Ubuntu

If you are using Ubuntu, you can run the following commands to setup an environment to build and test scx_rust_scheduler:

• install a sched_ext Ubuntu kernel and all the required user-space dependencies:

$ sudo add-apt-repository -y --enable-source ppa:arighi/sched-ext
$ sudo apt update -y
$ sudo apt dist-upgrade -y
$ sudo apt install -y rustc cargo libbpf-dev pkg-config clang

• reboot the system

Getting Started

• Build the scheduler:

$ cargo build

• Enable the scheduler:

$ sudo ./target/debug/scx_rust_scheduler
Rust scheduler is enabled (CTRL+c to exit)

• Disable the scheduler:

^C
Rust scheduler is disabled
EXIT: Scheduler unregistered from user space

Setting up a virtual environment for testing

If your distro doesn't provide a kernel recent enough (>= v6.12), you can use virtme-ng to setup a testing environment to run your Rust scheduler.

Example:

• Install virtme-ng:

 $ pip install --break-sysmstem-packages virtme-ng

• Get the Rust scheduler template and build it:

 $ git clone https://github.com/arighi/scx_rust_scheduler.git
 $ cd scx_rust_scheduler
 $ cargo build

• Run the scheduler inside a virtme-ng session:

 $ vng --ssh -vr v6.13-rc1 -- ./target/debug/scx_rust_scheduler

• Test: now from another shell session run vng --ssh-client to get an interactive shell session where you can run commands to stress test your scheduler.

See also

• sched_ext schedulers and tools
• scx_rustland_core documentation

License

This software is licensed under the GNU General Public License version 2. See the LICENSE file for details.