I'm finding it very convenient to pass configuration and other data that is read or calculated once but then used many times throughout a program by using Perl's use mechanism. I'm doing this by exporting a hash into the caller's namespace. For example:

package Myconfiguration;

my %config;

sub import {
    my $callpkg = caller(0);
    my $expsym = $_[1];

    configure() unless %config;

    *{"$callpkg\::$expsym"} = \%config;
}

and then in other modules:

use MyConfiguration (loc_config_sym);

if ( $loc_config_sym{paramater} ) {
    # ... do stuff ...
}

However, I'm not sure about this as a best practice. Is it better to add a method that returns a hash ref with the data? Something else?