Instrumenting call sites.

[MacGregor, Duncan (GE Energy Management)]

I've been doing a little project in my spare time to instrument our call sites and check the number of receivers being seen by each site in a running system. As expected most sites only see one or two classes and so go through the fast path. There are however some sites which see slightly more receivers than our limit for the fast paths but are still getting called an awful lot. So I've got two questions.


  1.  What is the recommended maximum tree size and longest path for composed MethodHandles (can we push our fast path limit a little higher)?
  2.  What's my best option for connecting call sites to specific points in byte code and hence to their source locations? Should I simply use JDI method entry events on the fallback methods and work my way up the stack past any java.lang.invoke infrastructure? Knowing where these sites are might help us refactor the code to avoid too many receivers being seen.

Thanks for any help you can give.,

Duncan.