Software Architect's Handbook

Profiling an application

The first step is to profile the application. Profiling is an analysis of a software system that results in measurements of the system's execution. Development teams should not be guessing where performance issues exist, as they will not always be where you expect. Rather than guessing, development teams should be acquiring precise measurements. These measurements can then be used to make decisions. Examples include how much time a particular method takes to execute, how often a method is called, the time spent in communication, the amount of I/O that is taking place, and how much of the CPU and memory is being used.

There are profiling tools, called profilers, available that can be leveraged to profile an application. ...