G'Day, I didn't have an email addr so pasted into gist. Just wanted to explain things a bit better than could on twitter. Good luck!
Depends what you mean by CPU bound: bound by availability or speed.
If the CPUs themselves are hot, then this is easy. "mpstat -P ALL 1" will show the hot CPUs. If single threads are causing it, then "pidstat -t 1" will identify them (although, it could be a large thread pool competing). This approach identifies if something is resource constrained by CPUs, but not bound by their speed.
Imagine a single CPU system running at 10% utilization, with an application processing 1 request per second, which is taking 100ms, all CPU time. The application's performance is CPU (speed) bounded, but the system looks mostly idle. This can be identified using walltime vs CPU time for the request. Most languages have a way to get the CPU time (something getrusage() related). Eg, if you were able to measure that the request took 100 ms, and, 100 ms of CPU time was consumed,