You are measuring the time for creating the array reference.
Don't do:
print sum([1..100_000]);
Do something like this:
#! /usr/bin/perl
# vim:ts=4 sw=4 sts=4 et nu fdc=3:
use strict;
use warnings;
use Benchmark qw( cmpthese );
#> sub routines
#> -------------------------------------------------------------------
+---------
sub sum_list {
my @numbers = @_;
my $sum = 0;
for my $num ( @numbers ) {
$sum += $num;
}
return $sum;
}
sub sum_by_ref {
my ( $numbers_ref ) = @_;
my $sum = 0;
for my $num ( @$numbers_ref ) {
$sum += $num;
}
return $sum;
}
#> main script
#> -------------------------------------------------------------------
+---------
my @numbers = 1 .. 1_000_000;
cmpthese( -1, {
'sum_list' => sub { sum_list(@numbers); },
'sum_by_ref' => sub { sum_by_ref(\@numbers); },
});
__END__
Result:
Rate sum_list sum_by_ref
sum_list 4.42/s -- -45%
sum_by_ref 8.00/s 81% --
I hope my point got clear ;o)
Addendum: Tested with creating list and reference directly within function call:
cmpthese( -1, {
'sum_list' => sub { sum_list(1..1_000_000); },
'sum_by_ref' => sub { sum_by_ref([1..1_000_000]); },
});
Result:
Rate sum_list sum_by_ref
sum_list 4.13/s -- -9%
sum_by_ref 4.55/s 10% --
edit: fixed missing "
1.." in last snippet. Thanks
ikegami. And fixed result output as well.