use strict;
use Benchmark qw(cmpthese);

my $module1 = 'Z';
my $module2 = 'Z::X';

cmpthese(
         0,
         {
             evalSTR1 => sub {
                 eval "use $module1";
                 delete $INC{'Z.pm'}
             },
             evalSTR2 => sub {
                 eval "use $module2";
                 delete $INC{'Z/X.pm'};
             },
             req1 => sub {
                 (my $pm = $module1) =~ s.::./.g;
                 $pm .= '.pm';
                 eval { require $pm };
                 delete $INC{'Z.pm'}
             },
             req2 => sub {
                 (my $pm = $module2) =~ s.::./.g;
                 $pm .= '.pm';
                 eval { require $pm };
                 delete $INC{'Z/X.pm'}
             },
         }
        );