baz.pl

use strict;
use warnings;
use Benchmark qw/cmpthese/;

sub ret_by_value {
    my $n = shift;
    my @seq = (0..$n);
    return @seq;
}

sub ret_by_ref {
    my $n = shift;
    my @seq = (0..$n);
    return \@seq;
}

cmpthese(10000, {
    v => sub { (ret_by_value(10000))[0]},
    r => sub { (ret_by_ref(10000))->[0] },
});