Rust Atomics and Locks

Chapter 5. Building Our Own Channels

Channels can be used to send data between threads, and they come in many variants. Some channels can only be used between exactly one sender and one receiver, while others can send from any number of threads, or even allow multiple receivers. Some channels are blocking, meaning that receiving (and sometimes sending) is a blocking operation, making your thread sleep until the operation can be completed. Some channels are optimized for throughput, while others are optimized for low latency.

The variations are endless, and there is no one-size-fits-all version that fits all use cases.

In this chapter, we’ll implement a few relatively simple channels to not only explore some more applications of atomics, but also to learn more about how our requirements and assumptions can be captured in Rust’s type system.

A Simple Mutex-Based Channel

A basic channel implementation does not require any knowledge of atomics. We can take a VecDeque, which is basically a Vec that allows for efficient adding and removing of elements on both ends, and protect it with a Mutex to allow multiple threads to access it. We then use the VecDeque as a queue of data, often called messages, that’s been sent but not yet received. Any thread that wants to send a message can simply add it to the back of the queue, and any thread that wants to receive a message just has to remove one from the front of the queue.

There’s just one more thing to add, which is used to make the ...