Rust: learning how to share a queue between threads

dbeck.github.io

27 points·dbeck74··6 comments

http://rustbyexample.com/std_misc/channels.html

This is how you share a queue between threads, the title is super-clickbait. It doesn't seem a surprise that stdlib doesn't have a circular buffer, I have no idea what it'd be used for?

I believe a channel can only have one receiver and one sender, no? So you can't share the channel between multiple workers.

This is the case for spsc (single producer, single consumer) channels, but the example I posted is for a mpsc (multiple producer single consumer) channel. Any number of threads can push data into it, as the example shows!

Having multiple receivers is slightly more complex, and you can't use std::sync::mpsc (obviously) but they are also possible.

What your link shows is the usage of the channels. My post was about how to actually implement a similar thing.

If you're curious check out oyashio: https://github.com/viperscape/oyashio It's a thread safe spmc in Rust that uses promises underneath. If I were to rewrite it, I'd use a Vec with promises and a cursor of sorts, instead of the of linked list I came up with.

You could also use this https://doc.rust-lang.org/std/sync/struct.Condvar.html (all block, notify one) to implement a "work stealing" style multiple consumers channel that'd be pretty cool. I think various incantations of this have been in and out of Rust's stdlib (I couldn't tell you why though?).

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