Software Architect's Handbook

Instrumentation

When instrumentation is used, code is added to the software system being profiled in order to collect information. For example, to collect data on the time spent in a method and to get a count of how many times the method is used, instrumentation code is executed at the beginning and end of the method.

Instrumentation code can be manually added by the development team. However, profilers can add instrumentation automatically. Some profilers that use instrumentation modify source code, while others work at runtime. Either way, instrumentation can provide a great level of detail. However, a disadvantage of instrumentation is that the instrumentation code can affect the measurements. The degree of the effect really depends on ...