optcarrot, is a headless NES emulator that the Ruby core team are using as a CPU-intensive optimization target.

ruby-prof supports excluding specific methods and threads from profiling results. This is useful for reducing connectivity in the call graph, making it easier to identify the source of performance problems when using a graph printer. For example, consider Integer#times: it's hardly ever useful to know how much time is spent in the method itself. We are more interested in how much the passed in block contributes to the time spent in the method which contains the Integer#times call. The effect on collected metrics are identical to eliminating methods from the profiling result in a post process step.