karls-mac-mini:monks karl$ ./forker.pl
numbers: 2000
processes: 4
fork: 31.1171970367432
for: 40.2419550418854

##</code><code>##

while(defined( my $number = $iterator->())) {
    $pm->start($number) and next;
    my $factorial = Math::BigInt->bfac($number);
    $pm->finish( 0, \$factorial );
}
$pm->wait_all_children;


##</code><code>##

for my $number (@numbers) {
    $pm->start($number) and next;
    my $factorial = Math::BigInt->bfac($number);
    $pm->finish( 0, \$factorial );
}
$pm->wait_all_children;