I'd like the ability to find out how often each output attribute/filter is being applied, so I need per action granularity and I would like my solution to be as efficient/scalable as possible. The perfmon counters (application-wide) (as answered below) are very handy, but I'd like the per action granularity.
I'd be open for a database solution, but it's not preferred, if I went down this route, how would I insert into the database (for when a response is cached), would I have to subclass Outputcache, and write some code in the constructor?
I'd also be open for logging something out to a file? But again it looks like I'd need to subclass.
I'd also be open to Google analytics type approaches, whereby the user response get's it back.
Is there a way to put a 'cached' marker in my http header? This could be used as an identifier as well.