Depending on what you mean by "profiling" you can inject Perl (?{code}) snippets into your regex to record the current time. (IMHO that's the most likely approach a third party profiler would take)

But please be aware that you might get a Heisenbug situation then, because your snippet was hindering some of the many internal heuristics or optimizations.

Looking into re debug mode before and after those injections is always a good approach.