This book provides some code performance optimization tricks, tips, and suggestions. Most of the contents in this book are made based on the official standard Go compiler and runtime implementation.

Life is full of trade-offs, the programming world is, too. In programming, we often need to make trade-offs between code readability, maintainability, development efficiency, and program efficiency, etc. Even for one of the aspects, there are also trade-offs needing to be made. Taking program efficiency for an example, we might need to make trade-offs between memory saving, code execution speed, and implementation difficulty, etc.

In practice, most parts of the code base of a project don't need to be implemented with high performances. Keeping them maintainable and readable is often more important (than making them memory saving and run very fast). The suggestions made in this book are just for the code parts which implementations really need to be high performant. Some of the suggestions often causes more verbose code. And please note that some of the suggested implementation might only be performant at some certain scenarios, and might be not at others.

The contents in this book include:

• how to consume less CPU resources.
• how to consume less memory.
• how to make less memory allocations.
• how to control memory allocation places.
• how to reduce garbage collection pressure.

This book neither explain how to use performance analysis tools, such as pprof, nor try to study deeply on compiler and runtime implementation details. None of the contents provided in this book make use of unsafe pointers and cgo. And the book also doesn't talk about algorithms. In other words, this book tries to provide some optimization suggestions in a way which is clear and easy to understand, for daily general Go programming.

This book collects many details and provides several tips in Go programming. The details and tips are categorized into

• syntax and semantics related
• conversions related
• comparisons related
• runtime related
• standard packages related

Most of the details are Go specific, but several of them are language independent.

Starting from version 1.18, Go has supported custom generics.

This book talks about the custom generics feature of Go programming language. The content in this book includes:

• custom generic syntax
• type constraints and type parameters
• type arguments and type inference
• how to write valid custom generic code
• current implementation/design restrictions

A reader needs to be familiar with Go general programming to read this book. In particular, readers of this book should be familiar with Go type system, including Go built-in generics, which and Go custom generics are two different systems.

Currently, the book mainly focuses on the syntax of, and concepts in, custom generics. More practical examples will be provided when I get more experiences of using custom generics.