I have instrumented my application with "stop watches". There is usually one such stop watch per (significant) function. These stop watches measure real time, thread time (and process time, but process time seems less useful) and call count. I can obviously sort the individual stop watches using either of the four values as a key. However that is not always useful and requires me to, e.g., disregard top level functions when looking for optimization opportunities, as top level functions/stop watches measure pretty much all of the application's run time.
I wonder if there is any research regarding any kind of score or heuristics that would point out functions/stop watches that are worthy looking at and optimizing?