For example, I can easily define entry points for arbitrary functions. At run time I can choose which entry point to call and benchmark that entry point using existing performance benchmarking tools like the very powerful and comprehensive "perf" tool on linux. This provides a very powerful way to analyze the performance for free and in a convenient manner with little instrumentation. I do not want the main entry point to be clobbered for such things. Ideally I would just use a simple annotation for any arbitrary function to convert it into an entry point that can be chosen at runtime. I am just giving a general idea here without going into specifics.
-harendra