This book contains tips, tricks, and techniques to make new and existing PHP applications much faster and less resource-hungry. Pro PHP Application Performance will help you understand all the technologies and components which play a role in how well your applications run. When seconds can mean the difference between retaining a user and losing a user, it's important for all of us to have optimization as part of our project roadmap. But what components within your application should you analyze? How should you optimize? And how can you measure how well your application is performing? These are some of the questions that are answered in this book. Along the way you will also learn the "why" of optimizing. You'll discover why you should optimize a specific component, why selecting one function over another is beneficial, and how to find and use the optimization tools available to the open source community. You'll also learn how to deploy caching software as well as web server software.