Flume

A blazingly fast multi-producer, multi-consumer channel.

use std::thread;

fn main() {
    println!("Hello, world!");

    let (tx, rx) = flume::unbounded();

    thread::spawn(move || {
        (0..10).for_each(|i| {
            tx.send(i).unwrap();
        })
    });

    let received: u32 = rx.iter().sum();

    assert_eq!((0..10).sum::<u32>(), received);
}

Why Flume?

• Featureful: Unbounded, bounded and rendezvous queues
• Fast: Always faster than std::sync::mpsc and sometimes crossbeam-channel
• Safe: No unsafe code anywhere in the codebase!
• Flexible: Sender and Receiver both implement Send + Sync + Clone
• Familiar: Drop-in replacement for std::sync::mpsc
• Capable: Additional features like MPMC support and send timeouts/deadlines
• Simple: Few dependencies, minimal codebase, fast to compile
• Asynchronous: async support, including mix 'n match with sync code
• Ergonomic: Powerful select-like interface

Usage

To use Flume, place the following line under the [dependencies] section in your Cargo.toml:

flume = "x.y"

Cargo Features

Flume comes with several optional features:

• spin: use spinlocks instead of OS-level synchronisation primitives internally for some kind of data access (may be more performant on a small number of platforms for specific workloads)

• select: Adds support for the Selector API, allowing a thread to wait on several channels/operations at once

• async: Adds support for the async API, including on otherwise synchronous channels

• eventual-fairness: Use randomness in the implementation of Selector to avoid biasing/saturating certain events over others

You can enable these features by changing the dependency in your Cargo.toml like so:

flume = { version = "x.y", default-features = false, features = ["async", "select"] }

Benchmarks

Although Flume has its own extensive benchmarks, don't take it from here that Flume is quick. The following graph is from the crossbeam-channel benchmark suite.

Tests were performed on an AMD Ryzen 7 3700x with 8/16 cores running Linux kernel 5.11.2 with the bfq scheduler.

License

Flume is licensed under either of:

• Apache License 2.0, (http://www.apache.org/licenses/LICENSE-2.0)

• MIT license (http://opensource.org/licenses/MIT)