I am interested in potentially ARM-enabling JBoss (http://www.opengroup.org/management/arm/). WebSphere comes with a facility called "Request Metrics" that you can enable to gather performance metrics at key points within the application server (web container entry/exit, JDBC, EJB, JMS, and web services). You can also plug an ARM 4 agent into WebSphere to handle the request metrics in a more flexible manner. It seems like JBoss would benefit from having this feature, and I am willing to give it a shot.
With JBoss' AOP support, I think the arm enablement itself would be fairly straightforward, but my question is if any of the developers could point my in the right direction with respect to the specific container methods I could instrument. Initially, I would want to track:
Web container entry and exit JDBC getConnection JDBC execute and executeQuery
And later expand that to web services and JMS. I would want to instrument initially at the container level only, and not require instrumentation of individual applications.