Real-Time Interrupt-driven Concurrency

The hardware accelerated Rust RTOS

A concurrency framework for building real-time systems.

Features

• Tasks as the unit of concurrency [^1]. Tasks can be event triggered

(fired in response to asynchronous stimuli) or spawned by the application on demand.

• Message passing between tasks. Specifically, messages can be passed to

software tasks at spawn time.

• A timer queue [^2]. Software tasks can be delayed or scheduled to continue running

at some time in the future. This feature can be used to implement periodic tasks.

• Support for prioritization of tasks and, thus, preemptive multitasking.

• Efficient and data race free memory sharing through fine-grained *priority

based* critical sections [^1].

• Deadlock free execution guaranteed at compile time. This is a stronger

guarantee than what's provided by [the standard Mutex abstraction][std-mutex].

[std-mutex]: https://doc.rust-lang.org/std/sync/struct.Mutex.html

• Minimal scheduling overhead. The task scheduler has minimal software

footprint; the hardware does the bulk of the scheduling.

• Highly efficient memory usage: All the tasks share a single call stack and

there's no hard dependency on a dynamic memory allocator.

• All Cortex-M devices are fully supported.

• Most RISC-V devices are supported. Refer to the RTIC book)

to learn more about RISC-V backends, their particularities, and their limitations.

• This task model is amenable to known WCET (Worst Case Execution Time) analysis

and scheduling analysis techniques.

User documentation

Documentation for the development version.

API reference

[Community provided examples repo][examples]

[examples]: https://github.com/rtic-rs/rtic-examples

Chat

Join us and talk about RTIC in the [Matrix room][matrix-room].

Weekly meeting minutes can be found over at [RTIC HackMD][hackmd]

[matrix-room]: https://matrix.to/#/#rtic:matrix.org [hackmd]: https://rtic.rs/meeting

Contributing

New features and big changes should go through the RFC process in the [dedicated RFC repository][rfcs].

[rfcs]: https://github.com/rtic-rs/rfcs

Running tests locally

To check all tests locally, make sure you got QEMU (and ESP32 QEMU if so desired) then:

$ cargo xtask ci

To only format code before PR (included in ci above):

$ cargo xtask fmt

Clippy lints:

$ cargo xtask clippy

and so on. See cargo xtask --help for all options.

Acknowledgments

This crate is based on the [Real-Time For the Masses language][rtfm-lang] created by the Embedded Systems group at [Luleå University of Technology][ltu], led by [Prof. Per Lindgren][perl].

[rtfm-lang]: https://web.archive.org/web/20220401050805/http://www.rtfm-lang.org/ [ltu]: https://www.ltu.se/?l=en [perl]: https://www.ltu.se/staff/p/pln-1.11258?l=en

References

[^1]: Eriksson, J., Häggström, F., Aittamaa, S., Kruglyak, A., & Lindgren, P. (2013, June). Real-time for the masses, step 1: Programming API and static priority SRP kernel primitives. In Industrial Embedded Systems (SIES), 2013 8th IEEE International Symposium on (pp. 110-113). IEEE.

[^2]: Lindgren, P., Fresk, E., Lindner, M., Lindner, A., Pereira, D., & Pinho, L. M. (2016). Abstract timers and their implementation onto the arm cortex-m family of mcus. ACM SIGBED Review, 13(1), 48-53.

License

All source code (including code snippets) is licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or

[https://www.apache.org/licenses/LICENSE-2.0][L1])

• MIT license (LICENSE-MIT or

[https://opensource.org/licenses/MIT][L2])

[L1]: https://www.apache.org/licenses/LICENSE-2.0 [L2]: https://opensource.org/licenses/MIT

at your option.

The written prose contained within the book is licensed under the terms of the Creative Commons CC-BY-SA v4.0 license (LICENSE-CC-BY-SA or [https://creativecommons.org/licenses/by-sa/4.0/legalcode][L3]).

[L3]: https://creativecommons.org/licenses/by-sa/4.0/legalcode

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be licensed as above, without any additional terms or conditions.