Performance Testing is a testing to test an application performance, stress against load. Also it is a test to define that application has enough resources like Servers which are Application Server, Web Server etc. Not only to test resources but to test how many resources it is consuming. If application is consuming lot more than what expected also can be identified in performance testing. In a simple theory, if somebody is giving you a task he would thing whether you are capable or not before he assigns task to you. Same way in application aspect, we have to do performance testing to assume that application is capable enough in real world.

There are 3 Types of Performance testing and all of them are inter-related.

1) Load Testing
2) Performance Testing
3) Stress Testing

Using above three various testings we will have to identify application performance.