#!/usr/bin/perl
use strict;
use warnings;
use Benchmark qw':all :hireswallclock';
use threads;

cmpthese(10, {
    'while' => sub {
        my $i = 230000;
        my $k = 1;
        while ($i <= 900000) {
            $k *= $i++;
        }
        },
    'for' => sub {
        my $k = 1;
        for (230000 .. 900000) {
            $k *= $_;
        }
        },
    'threads' => sub {
        my $k = 1;
        my $thr2 = async {
            my $k = 1;
            my $i = 565001;
            while ($i <= 900000) {
                $k *= $i++;
            }

            };
        my $i = 230000;
        while ($i <= 565000) {
            $k *= $i++;
        }
        $k *= $thr2->join();
    }
});

##</code><code>##

          Rate threads   while     for
threads 3.09/s      --    -29%    -38%
while   4.33/s     40%      --    -13%
for     4.96/s     60%     15%      --