You don't trust it because it's simple?!

Well, I guess you still don't have that much experience, but here's a universal truth: the best code is usually the most simple. Usually.

Anyways, I don't know exactly how your program works, but I would first suggest to use you friend, Devel::Dprof.

( I'm not sure what you didn't understand about the output from Devel::Dprof, but it's pretty straight forward, I think.... It's just shows in order which subroutines were accessed most frequently )