I'm currently evaluating VTune for profiling our web application. It is built upon MS-IIS ASP Classic. Business logic is implemented using COM (inproc DLL's).
I do see that VTune can access ASP.NET (which I tried w/ our .NET portions of the app). But I have been unable to figure out how to connect to ASP classic (DLLHost.exe).
I have another tool from NuMega - DevPartner Studio. It allows me to instrument my DLL's and execute them - however it is implemented such that the profiling wrapper for my DLL's is out-of-process (causing my code to run out-of-process, you see a wrapper.exe running). The code can't run out of process because it uses ADO, which has a limitation that the Connection object must be created in the same process that the Recordset object is in.
So I'm looking for a new tool that monitors our application as is and doesn't drastically change the way it executes.
We had success with an Old version of VTune several years ago while at an IBM lab. IBM brought in an Intel engineer who used VTune. So we thought we'd give it a try. One of the guys who was present at the test seems to remember being able to choose a Process ID and have VTune attach to it.