Profiler - Choosing Type+Methods in each module for a web request

Hi,

Posting this question just to seek some ideas in selecting Type+methods in each module in a web request.

I am developing a .NET profiler to be deployed in a production server. If i instrument all the Type+methods in modules then i m getting more overhead for each web request.

I am seeking idea on how to decide on the type+methods in each module to instrument. On what basis should I decide on instrumenting the functions that are being jitted,..? 

Expecting some knowledge share in this case from the geeks..! 

Thanks 

Selva