| # Crossbeam |
| |
| []( |
| https://github.com/crossbeam-rs/crossbeam/actions) |
| []( |
| https://github.com/crossbeam-rs/crossbeam#license) |
| []( |
| https://crates.io/crates/crossbeam) |
| []( |
| https://docs.rs/crossbeam) |
| []( |
| https://www.rust-lang.org) |
| [](https://discord.com/invite/JXYwgWZ) |
| |
| This crate provides a set of tools for concurrent programming: |
| |
| #### Atomics |
| |
| * [`AtomicCell`], a thread-safe mutable memory location.<sup>(no_std)</sup> |
| * [`AtomicConsume`], for reading from primitive atomic types with "consume" ordering.<sup>(no_std)</sup> |
| |
| #### Data structures |
| |
| * [`deque`], work-stealing deques for building task schedulers. |
| * [`ArrayQueue`], a bounded MPMC queue that allocates a fixed-capacity buffer on construction.<sup>(alloc)</sup> |
| * [`SegQueue`], an unbounded MPMC queue that allocates small buffers, segments, on demand.<sup>(alloc)</sup> |
| |
| #### Memory management |
| |
| * [`epoch`], an epoch-based garbage collector.<sup>(alloc)</sup> |
| |
| #### Thread synchronization |
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| * [`channel`], multi-producer multi-consumer channels for message passing. |
| * [`Parker`], a thread parking primitive. |
| * [`ShardedLock`], a sharded reader-writer lock with fast concurrent reads. |
| * [`WaitGroup`], for synchronizing the beginning or end of some computation. |
| |
| #### Utilities |
| |
| * [`Backoff`], for exponential backoff in spin loops.<sup>(no_std)</sup> |
| * [`CachePadded`], for padding and aligning a value to the length of a cache line.<sup>(no_std)</sup> |
| * [`scope`], for spawning threads that borrow local variables from the stack. |
| |
| *Features marked with <sup>(no_std)</sup> can be used in `no_std` environments.*<br/> |
| *Features marked with <sup>(alloc)</sup> can be used in `no_std` environments, but only if `alloc` |
| feature is enabled.* |
| |
| [`AtomicCell`]: https://docs.rs/crossbeam/*/crossbeam/atomic/struct.AtomicCell.html |
| [`AtomicConsume`]: https://docs.rs/crossbeam/*/crossbeam/atomic/trait.AtomicConsume.html |
| [`deque`]: https://docs.rs/crossbeam/*/crossbeam/deque/index.html |
| [`ArrayQueue`]: https://docs.rs/crossbeam/*/crossbeam/queue/struct.ArrayQueue.html |
| [`SegQueue`]: https://docs.rs/crossbeam/*/crossbeam/queue/struct.SegQueue.html |
| [`channel`]: https://docs.rs/crossbeam/*/crossbeam/channel/index.html |
| [`Parker`]: https://docs.rs/crossbeam/*/crossbeam/sync/struct.Parker.html |
| [`ShardedLock`]: https://docs.rs/crossbeam/*/crossbeam/sync/struct.ShardedLock.html |
| [`WaitGroup`]: https://docs.rs/crossbeam/*/crossbeam/sync/struct.WaitGroup.html |
| [`epoch`]: https://docs.rs/crossbeam/*/crossbeam/epoch/index.html |
| [`Backoff`]: https://docs.rs/crossbeam/*/crossbeam/utils/struct.Backoff.html |
| [`CachePadded`]: https://docs.rs/crossbeam/*/crossbeam/utils/struct.CachePadded.html |
| [`scope`]: https://docs.rs/crossbeam/*/crossbeam/fn.scope.html |
| |
| ## Crates |
| |
| The main `crossbeam` crate just [re-exports](src/lib.rs) tools from |
| smaller subcrates: |
| |
| * [`crossbeam-channel`](crossbeam-channel) |
| provides multi-producer multi-consumer channels for message passing. |
| * [`crossbeam-deque`](crossbeam-deque) |
| provides work-stealing deques, which are primarily intended for building task schedulers. |
| * [`crossbeam-epoch`](crossbeam-epoch) |
| provides epoch-based garbage collection for building concurrent data structures. |
| * [`crossbeam-queue`](crossbeam-queue) |
| provides concurrent queues that can be shared among threads. |
| * [`crossbeam-utils`](crossbeam-utils) |
| provides atomics, synchronization primitives, scoped threads, and other utilities. |
| |
| There is one more experimental subcrate that is not yet included in `crossbeam`: |
| |
| * [`crossbeam-skiplist`](crossbeam-skiplist) |
| provides concurrent maps and sets based on lock-free skip lists. |
| |
| ## Usage |
| |
| Add this to your `Cargo.toml`: |
| |
| ```toml |
| [dependencies] |
| crossbeam = "0.8" |
| ``` |
| |
| ## Compatibility |
| |
| Crossbeam supports stable Rust releases going back at least six months, |
| and every time the minimum supported Rust version is increased, a new minor |
| version is released. Currently, the minimum supported Rust version is 1.38. |
| |
| ## Contributing |
| |
| Crossbeam welcomes contribution from everyone in the form of suggestions, bug reports, |
| pull requests, and feedback. 💛 |
| |
| If you need ideas for contribution, there are several ways to get started: |
| |
| * Found a bug or have a feature request? |
| [Submit an issue](https://github.com/crossbeam-rs/crossbeam/issues/new)! |
| * Issues and PRs labeled with |
| [feedback wanted](https://github.com/crossbeam-rs/crossbeam/issues?utf8=%E2%9C%93&q=is%3Aopen+sort%3Aupdated-desc+label%3A%22feedback+wanted%22+) |
| need feedback from users and contributors. |
| * Issues labeled with |
| [good first issue](https://github.com/crossbeam-rs/crossbeam/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc+label%3A%22good+first+issue%22) |
| are relatively easy starter issues. |
| |
| #### RFCs |
| |
| We also have the [RFCs](https://github.com/crossbeam-rs/rfcs) repository for more |
| high-level discussion, which is the place where we brainstorm ideas and propose |
| substantial changes to Crossbeam. |
| |
| You are welcome to participate in any open |
| [issues](https://github.com/crossbeam-rs/rfcs/issues?q=is%3Aissue+is%3Aopen+sort%3Aupdated-desc) |
| or |
| [pull requests](https://github.com/crossbeam-rs/rfcs/pulls?q=is%3Apr+is%3Aopen+sort%3Aupdated-desc). |
| |
| #### Learning resources |
| |
| If you'd like to learn more about concurrency and non-blocking data structures, there's a |
| list of learning resources in our [wiki](https://github.com/crossbeam-rs/rfcs/wiki), |
| which includes relevant blog posts, papers, videos, and other similar projects. |
| |
| Another good place to visit is [merged RFCs](https://github.com/crossbeam-rs/rfcs/tree/master/text). |
| They contain elaborate descriptions and rationale for features we've introduced to |
| Crossbeam, but keep in mind that some of the written information is now out of date. |
| |
| #### Conduct |
| |
| The Crossbeam project adheres to the |
| [Rust Code of Conduct](https://www.rust-lang.org/policies/code-of-conduct). |
| This describes the minimum behavior expected from all contributors. |
| |
| ## License |
| |
| Licensed under either of |
| |
| * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0) |
| * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT) |
| |
| at your option. |
| |
| Some Crossbeam subcrates have additional licensing notices. |
| Take a look at other readme files in this repository for more information. |
| |
| #### 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 |
| dual licensed as above, without any additional terms or conditions. |
