Real-World Solutions for Developing High-Quality PHP Frameworks and Applications

Chapter 15. Performance Testing

Brian Shire

WHAT'S IN THIS CHAPTER?

• Overview of performance-testing tools

• Test environment considerations

• Load testing tools

• Resource usage monitoring tools

• System metrics tools

• Performance testing pitfalls

INTRODUCTION

Two primary questions must be answered when performance testing:

1. Is there a need for optimization?

   • Is the application currently meeting performance requirements?

   • Will users be satisfied with the responsiveness of the site?

   • Is the site stable?

   • Are the infrastructure costs reasonable or prohibitive?

   • Will the above questions hold true if usage increases exponentially?

   • How do the above factors weigh against other business priorities, such as delivering new features, fixing bugs, maintaining existing services, and so on?

2. What specifically should be optimized?

   • Where should we begin looking for optimizations?

   • What optimizations have the greatest gains for the least amount of work, time, and money?

   • How can future limitations be identified as the application grows or changes?

Some of the items listed above are easy to execute, because a variety of tools can help developers to immediately answer these questions. Other questions require an understanding of the application or an insight that comes only with experience on a given project and optimizing PHP applications in particular.

In this chapter, we present common tools and the experiences from having used them for PHP performance testing. This should provide a foundation on which to build further experience for ...