What you are trying to benchmark is loading time, so keep that in mind. I can think of two ways to benchmark achive that aim.

The first is timing with some tool the times (under unix use times, otherwise use Benchmark to time the system("..."); function from perl). Use the command lines:

perl -e ""
perl -e "use CGI ':standard';"
perl -e "use HTML::Entities"
[download]

Otherwise the data you want may be attainable through Devel::DProf, which is useful for seeing all bottlenecks, in compile or runtime.