Book Image

Effective Concurrency in Go

By : Burak Serdar
Book Image

Effective Concurrency in Go

By: Burak Serdar

Overview of this book

The Go language has been gaining momentum due to its treatment of concurrency as a core language feature, making concurrent programming more accessible than ever. However, concurrency is still an inherently difficult skill to master, since it requires the development of the right mindset to decompose problems into concurrent components correctly. This book will guide you in deepening your understanding of concurrency and show you how to make the most of its advantages. You’ll start by learning what guarantees are offered by the language when running concurrent programs. Through multiple examples, you will see how to use this information to develop concurrent algorithms that run without data races and complete successfully. You’ll also find out all you need to know about multiple common concurrency patterns, such as worker pools, asynchronous pipelines, fan-in/fan-out, scheduling periodic or future tasks, and error and panic handling in goroutines. The central theme of this book is to give you, the developer, an understanding of why concurrent programs behave the way they do, and how they can be used to build correct programs that work the same way in all platforms. By the time you finish the final chapter, you’ll be able to develop, analyze, and troubleshoot concurrent algorithms written in Go.
Table of Contents (13 chapters)

The happened-before relationship between memory operations

It all comes down to how memory operations are ordered at runtime, and how the runtime guarantees when the effects of those memory operations are observable. To explain the Go memory model, we need to define three relationships that define different orderings of memory operations.

In any goroutine, the ordering of memory operations must correspond to the correct sequential execution of that goroutine as determined by the control flow statements and expression evaluation order. This ordering is the sequenced-before relationship. This, however, does not mean that the compiler has to execute a program in the order it is written. The compiler can rearrange the execution order of statements as long as a memory read operation of a variable reads the last value written to that variable.

Let’s refer to the following program:

1: x=1
2: y=2
3: z=x
4: y++
5: w=y

The z variable will always be set to 1, and the w variable...