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Snapshot 0 · 2026-11-04T12:47:23Z · Rust · Apache-2.0
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Tools for concurrent programming in Rust
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# 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 * [`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/latest/crossbeam/atomic/struct.AtomicCell.html [`AtomicConsume`]: https://docs.rs/crossbeam/latest/crossbeam/atomic/trait.AtomicConsume.html [`deque`]: https://docs.rs/crossbeam/latest/crossbeam/deque/index.html [`ArrayQueue`]: https://docs.rs/crossbeam/latest/crossbeam/queue/struct.ArrayQueue.html [`SegQueue`]: https://docs.rs/crossbeam/latest/crossbeam/queue/struct.SegQueue.html [`channel`]: https://docs.rs/crossbeam/latest/crossbeam/channel/index.html [`Parker`]: https://docs.rs/crossbeam/latest/crossbeam/sync/struct.Parker.html [`ShardedLock`]: https://docs.rs/crossbeam/latest/crossbeam/sync/struct.ShardedLock.html [`WaitGroup`]: https://docs.rs/crossbeam/latest/crossbeam/sync/struct.WaitGroup.html [`epoch`]: https://docs.rs/crossbeam/latest/crossbeam/epoch/index.html [`Backoff`]: https://docs.rs/crossbeam/latest/crossbeam/utils/struct.Backoff.html [`CachePadded`]: https://docs.rs/crossbeam/latest/crossbeam/utils/struct.CachePadded.html [`scope`]: https://docs.rs/crossbeam/latest/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 one year, and every time the minimum supported Rust version is increased, a new minor version is released. Currently, the minimum supported Rust version is 1.74. ## 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/HEAD/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.