Most likely a better solution would be to use object oriented techniques. Define an "interface" (methods that are expected to be supplied by an object) then have each of your "worker" modules register themselves when they are loaded by pushing a worker object into a list. Something like:

use strict;
use warnings;

our @Workers;

package Worker1;

push @Workers, Worker1->new();

sub new {
    return bless {}, __PACKAGE__;
}

sub doStuff {
    print __PACKAGE__ . " reporting for duty\n";
}


package Worker2;

push @Workers, Worker2->new();

sub new {
    return bless {}, __PACKAGE__;
}

sub doStuff {
    print __PACKAGE__ . " standing by\n";
}


package main;

for my $worker (@Workers) {
    $worker->doStuff();
}
[download]

Prints:

Worker1 reporting for duty
Worker2 standing by
[download]

In practise each package would be in a different module file. Now each worker object keeps its own state so globals aren't needed.