I'm tempted to relabel this question 'Look at this brick. What type of house does it belong to?'

Here's the situation: I've effectively been asked to profile some subroutines having access to neither profilers (even Devel::DProf) nor Time::HiRes. The purpose of this exercise is to 'locate' bottlenecks.

At the moment, I'm sprinkling print statements at the beginning and end of each sub that log entries and exits to file, along with the result of the time function. Not ideal, but it's the best I can go by given the circumstances. At the very least it'll allow me to see how many times each sub is called.

The code is running under Unix. The closest thing I see to my need is perlfaq8, but that doesn't seem to help (I don't know how to make a syscall, and am wondering if it'll affect the code timing unpredictably).

Not your typical everyday SO question...