FWIW, strftime is damn handy for date subtraction and addition if you don't want to use heavy weighted modules like DateTime. I've had great success with it, see for more information:

How Do I Get Yesterday's Date Using localtime.

So in this case, strftime would be more useful if you had a date/time and an interval to add/subtract. There are many other modules and benchmarks for benchmarking. brian_d_foy has a great section on Benchmarking in his Mastering Perl book.

For higher level profiling, you should look at Devel::NYTProf.