A fast rendezvous in rust where data can optionally be swapped between the two threads.

Overview

rendezvous_swap

A rendezvous is an execution barrier between a pair of threads, but this crate also provides the option of swapping data at the synchronisation point. (Terminology is from The Little Book of Semaphores)

This is mainly intended for situations where threads sync frequently. Unlike a normal spinlock, it does not use any CAS instructions, just [Acquire] loads and [Release] stores which means it can compile to just a handful of non atomic instructions on x86_64. Because the crate uses atomics for synchronisation, it is also no_std.

Data is internally swapped with pointers, so large structures are not costly to swap and therefore do not need to be boxed.

In microbenchmarks on a i5-7200U CPU, it takes less than 100 ns to swap data.

Safety

[RendezvousData] contains unsafe but all tests pass when running with Miri.

Example: Sync thread execution

use rendezvous_swap::Rendezvous;
use std::thread;

let (mut my_rendezvous, mut their_rendezvous) = Rendezvous::new();
thread::spawn(move || {
    for i in 1..5 {
        println!("{i}");
        their_rendezvous.wait();
    }
});
for i in 1..5 {
    println!("{i}");
    my_rendezvous.wait();
}

This prints:

1
1
2
2
3
3
4
4

Example: Swap thread data

use std::thread;
use rendezvous_swap::RendezvousData;

let (mut my_rendezvous, mut their_rendezvous) = RendezvousData::new(0, 0);
let handle = thread::spawn(move || {
    let borrow = their_rendezvous.swap();
    *borrow = 3;

    let borrow = their_rendezvous.swap();
    assert_eq!(7, *borrow);
});
let borrow = my_rendezvous.swap();
*borrow = 7;

let borrowed_data = my_rendezvous.swap();
assert_eq!(3, *borrowed_data);

Example: Safety

The following won't compile due to the limited lifetime of the references provided by [RendezvousData::swap], you will get the familiar lifetime errors as if you are borrowing a struct element. This crate is safe because it is not possible for both threads to have mutable references to the same memory location at the same time.

use std::thread;
use rendezvous_swap::RendezvousData;

let (mut my_rendezvous, mut their_rendezvous) = RendezvousData::new(0, 0);
let handle = thread::spawn(move || {
    their_rendezvous.swap(); // swap return values can be ignored
    their_rendezvous.swap();
});
let old_borrow = my_rendezvous.swap(); // first mutable borrow occurs here

let new_borrow = my_rendezvous.swap(); // second mutable borrow occurs here

*old_borrow = 3; // first borrow is later used here

Current version: 0.1.0

License: GPL-3.0

You might also like...
In this repository you can find modules with code and comments that explain rust syntax and all about Rust lang.
In this repository you can find modules with code and comments that explain rust syntax and all about Rust lang.

Learn Rust What is this? In this repository you can find modules with code and comments that explain rust syntax and all about Rust lang. This is usef

🦀 Rust crate that allows creating weighted prefix trees that can be used in autocomplete

weighted_trie 🦀 Rust crate that allows creating weighted prefix trees that can be used in autocomplete Released API Docs Quickstart To use weigthed-t

Charted's email service built in Rust that can be connected via gRPC

email-service is a small microservice to help transfer emails towards other people without trying to implement it in different languages. This is used in charted-server for member invitations, passwordless authentication, and more.

Grimsby is an Erlang Port written in Rust that can close its standard input while retaining standard output (and error)

Grimsby An Erlang Port provides the basic mechanism for communication from Erlang with the external world. From the Ports and Port Drivers: Erlang Ref

A rust crate can find first `Err` in `IteratorResultT, E` and iterating continuously, without allocation.

Api Document first-err Find the first Err in IteratorResultT, E and allow iterating continuously. This crate is specifically designed to replace t

Core Temporal SDK that can be used as a base for language specific Temporal SDKs

Core SDK that can be used as a base for all other Temporal SDKs. Getting started See the Architecture doc for some high-level information. This repo u

A Matrix bot which can generate
A Matrix bot which can generate "This Week in X" like blog posts

hebbot A Matrix bot which can help to generate periodic / recurrent summary blog posts (also known as "This Week in X"). The bot was inspired by twim-

Cogo is a high-performance library for programming stackful coroutines with which you can easily develop and maintain massive concurrent programs.
Cogo is a high-performance library for programming stackful coroutines with which you can easily develop and maintain massive concurrent programs.

Cogo is a high-performance library for programming stackful coroutines with which you can easily develop and maintain massive concurrent programs.

Custom deserialization for fields that can be specified as multiple types.

serde-this-or-that Custom deserialization for fields that can be specified as multiple types. This crate works with Cargo with a Cargo.toml like: [dep

Owner
Erik
I enjoy programming, computer architecture, shaders and math.
Erik
A typemap for a set of known types optionally without heap allocation, and supporting iterating by traits

fixed_typemap docs.rs GitHub Sponsors Implements typemaps that support a lot of extra funcctionality using procedural macros. docs.rs has a lot more t

Austin Hicks 2 Dec 27, 2021
Reverse-engineered Rust client for Instagram's Threads app.

Instagram Threads API Unofficial, Reverse-Engineered Rust client for Instagram's Threads. Usage use threads_api::Threads; let client = Threads::new()

Miguel Piedrafita 66 Jul 12, 2023
A library for transcoding between bytes in Astro Notation Format and Native Rust data types.

Rust Astro Notation A library for transcoding between hexadecimal strings in Astro Notation Format and Native Rust data types. Usage In your Cargo.tom

Stelar Software 1 Feb 4, 2022
The Fast Vector Similarity Library is designed to provide efficient computation of various similarity measures between vectors.

Fast Vector Similarity Library Introduction The Fast Vector Similarity Library is designed to provide efficient computation of various similarity meas

Jeff Emanuel 243 Sep 6, 2023
List public items (public API) of Rust library crates. Enables diffing public API between releases.

cargo wrapper for this library You probably want the cargo wrapper to this library. See https://github.com/Enselic/cargo-public-items. public_items Li

Martin Nordholts 20 Dec 26, 2022
A simple programming language for something between C and Rust.

inuc inuc is a systems programming language that is something between C and Rust. Features : [] Strong , static typing (type inference not a priority

Sagnik Chatterjee 1 Feb 7, 2022
An expression based data notation, aimed at transpiling itself to any cascaded data notation.

Lala An expression oriented data notation, aimed at transpiling itself to any cascaded data notation. Lala is separated into three components: Nana, L

null 37 Mar 9, 2022
Converts between country names, ISO 3166-1 codes and flag emojis.

country-emoji Converts between country names, ISO 3166-1 codes and flag emojis. Usage use country_emoji::{flag, code, name, countries}; flag("CL") /

Leo Dutra 4 Oct 25, 2022
Rust 核心库和标准库的源码级中文翻译,可作为 IDE 工具的智能提示 (Rust core library and standard library translation. can be used as IntelliSense for IDE tools)

Rust 标准库中文版 这是翻译 Rust 库 的地方, 相关源代码来自于 https://github.com/rust-lang/rust。 如果您不会说英语,那么拥有使用中文的文档至关重要,即使您会说英语,使用母语也仍然能让您感到愉快。Rust 标准库是高质量的,不管是新手还是老手,都可以从中

wtklbm 493 Jan 4, 2023
TypeRust - simple Rust playground where you can build or run your Rust code and share it with others

Rust playground Welcome to TypeRust! This is a simple Rust playground where you can build or run your Rust code and share it with others. There are a

Kirill Vasiltsov 28 Dec 12, 2022