You might also be interested in using a profile. Devel::NYTProf is a very good and informative profiler, it makes it quite easy to spot bottlenecks in your programs.
Perl 6 - links to (nearly) everything that is Perl 6.
Comment on Re: How to measure execution time in Perl
I'd just like to add that Devel::NYTProf supports multiple ways to measure the time it takes to run some code. The documentation is great, and it covers the benefits and problems associated with each profiling method. You can learn a lot without ever using the module.