Well I think you have to refine your question a bit. CA/Wily Introscope use for system profiling and diagnostic information in the same way that you would use some of the deep diagnostic probes available in the HP/Merc performance solutions. While Introscope adds overhead while monitoring the systems it is not a "load testing tool" You would still need to have LoadRunner/SilkPerformer/e-Load or whatever to generate load on the infrastructure.
If your question is more how does introscope compare the the HP/Merc diagnostics then my answer is they both get you similar info. I have found that setting up the Wily software is a bit easier than the Merc. However, I have also found that buying solutions from different vendors can lead to lots more $$$ ...
I need to do load testing on WAS. There is already a Introscope monitoring it. So I can use the load runner for the load testing. But do I need to configure the WAS for load runner? SO there would be two different sets from 2 different tools. Or could I just run the load runner on the application deployed on WAS for the load testing?
I did contact them but HP support doesn't know anything about introscope. As I have this tool already monitoring the WAS what would be the steps for load testing. WOuld it be different then normal configuration.
HP Diagnostics would be able to tie your transactions to the server side monitors from the information gathered via the probes.
Introscope would not be able to do this as it has no load generating capability (certainly none that comes anywhere near Loadrunner)
Intrascope is great for production monitoring .... not so good in the test arena, but if thats all you got then better than nothing.