Are you also having same question as that of John ?
John : I am clueless how do i get started with performance testing ?
John : What do I need to know about web application before getting started ?
John : What are the tools that can help me understand my application ?
John : How do performance testing tool work ?
John : How do I choose a right tool for performance testing ?
John : How do i come up with various scenarios ?
Well then you are at right place .