You can also try to measure the startup and initialization phase, and see if it's large enough to warrant the effort.

#!/usr/bin/perl
use Time::HiRes qw(time);
my $start; BEGIN { $start = time() };

# rest of module loading here
# then initialization (open database connections etc.)
warn "Startup time: ", time() - $start; 

# rest of script goes here
[download]

wouldn't that first $start be called AFTER the compilation, though? (thank you, by the way, for your help!)

No, that's why I put the initialization in a BEGIN block - that means it's run immediately after that block is parsed. (Sure, it misses a small part of the compilation phase, but if you load many modules that part is really small compared to the rest).