Book Image

Hands-On Concurrency with Rust

By : Brian L. Troutwine
Book Image

Hands-On Concurrency with Rust

By: Brian L. Troutwine

Overview of this book

Most programming languages can really complicate things, especially with regard to unsafe memory access. The burden on you, the programmer, lies across two domains: understanding the modern machine and your language's pain-points. This book will teach you to how to manage program performance on modern machines and build fast, memory-safe, and concurrent software in Rust. It starts with the fundamentals of Rust and discusses machine architecture concepts. You will be taken through ways to measure and improve the performance of Rust code systematically and how to write collections with confidence. You will learn about the Sync and Send traits applied to threads, and coordinate thread execution with locks, atomic primitives, data-parallelism, and more. The book will show you how to efficiently embed Rust in C++ code and explore the functionalities of various crates for multithreaded applications. It explores implementations in depth. You will know how a mutex works and build several yourself. You will master radically different approaches that exist in the ecosystem for structuring and managing high-scale systems. By the end of the book, you will feel comfortable with designing safe, consistent, parallel, and high-performance applications in Rust.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell

Blocking until conditions change – condvar

One option is a condvar, or CONDition VARiable. Condvars are a nifty way to block a thread, pending a change in some Boolean condition. One difficulty is that condvars are associated exclusively with mutexes, but in this example, we don't mind all that much.

The way a condvar works is that, after taking a lock on a mutex, you pass the MutexGuard into Condvar::wait, which blocks the thread. Other threads may go through this same process, blocking on the same condition. Some other thread will take the same exclusive lock and eventually call either notify_one or notify_all on the condvar. The first wakes up a single thread, the second wakes up all threads. Condvars are subject to spurious wakeup, meaning the thread may leave its block without a notification being sent to it. For this reason condvars check their conditions in a loop. But, once the condvar wakes, you are guaranteed to hold the mutex, which prevents deadlocks on spurious wakeup.

Let's adapt...