scx/scheds/rust/scx_rustland/README.md
Andrea Righi cf43129d89 scx_rustland: update documentation
scx_rustland has significantly evolved since its original design.

With the introduction of scx_rustland_core and the inclusion of the
scx_rlfifo example, scx_rustland's focus can be shifted from solely
being an "easy-to-read Rust scheduler template" to a fully functional
scheduler.

For this reason, update the README and documentation to reflect its
revised design, objectives, and intended use cases.

Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
2024-02-28 17:49:44 +01:00

48 lines
2.1 KiB
Markdown

# scx_rustland
This is a single user-defined scheduler used within [sched_ext](https://github.com/sched-ext/scx/tree/main), which is a Linux kernel feature which enables implementing kernel thread schedulers in BPF and dynamically loading them. [Read more about sched_ext](https://github.com/sched-ext/scx/tree/main).
## Overview
scx_rustland is made of a BPF component (scx_rustland_core) that implements the
low level sched-ext functionalities and a user-space counterpart (scheduler),
written in Rust, that implements the actual scheduling policy.
## How To Install
Available as a [Rust crate](https://crates.io/crates/scx_rustland): `cargo add scx_rustland`
## Typical Use Case
scx_rustland is designed to prioritize interactive workloads over background
CPU-intensive workloads. For this reason the typical use case of this scheduler
involves low-latency interactive applications, such as gaming, video
conferencing and live streaming.
scx_rustland is also designed to be an "easy to read" template that can be used
by any developer to quickly experiment more complex scheduling policies fully
implemented in Rust.
## Production Ready?
Not quite. For production scenarios, other schedulers are likely to exhibit
better performance, as offloading all scheduling decisions to user-space comes
with a certain cost.
However, a scheduler entirely implemented in user-space holds the potential for
seamless integration with sophisticated libraries, tracing tools, external
services (e.g., AI), etc.
Hence, there might be situations where the benefits outweigh the overhead,
justifying the use of this scheduler in a production environment.
## Demo
[scx_rustland-terraria](https://github.com/sched-ext/scx/assets/1051723/42ec3bf2-9f1f-4403-80ab-bf5d66b7c2d5)
The key takeaway of this demo is to demonstrate that , despite the overhead of
running a scheduler in user-space, we can still obtain interesting results and,
in this particular case, even outperform the default Linux scheduler (EEVDF) in
terms of application responsiveness (fps), while a CPU intensive workload
(parallel kernel build) is running in the background.