#!/usr/local/bin/perl
use strict;
use warnings;
use Benchmark qw[ cmpthese timethese ];

package Benchmark;

my @keys = ('s', 'm' x 10, 'l' x 100, 'h' x 1_000, 'r' x 100_000);

sub test {
    my ($iters, $key) = @_;
    my %hash = ();
    # regardless of which key we use, build all the keys so the time
    # needed to clone a big string doesn't overshadow the time to clone
    # a small string.
    for (my $i = 0; $i < $iters; $i++) {
	$hash { (map { $_.$i } @keys)[$key] } = undef;
    }
}

my $many = 100;

cmpthese(5*$many, {
    'short' => sub { test($many, 0) },
    'medium' => sub { test($many, 1) },
    'long' => sub { test($many, 2) },
    'huge' => sub { test($many, 3) },
    'ridiculous' => sub { test($many, 4) },
});

__END__

laptop:~> monk.pl
Benchmark: timing 500 iterations of huge, long, medium, ridiculous, short...

laptop:~> monk.pl
Benchmark: timing 500 iterations of huge, long, medium, ridiculous, short...
      huge: 31 wallclock secs (31.57 usr +  0.00 sys = 31.57 CPU) @ 15.84/s (n=500)
      long: 32 wallclock secs (30.39 usr +  0.03 sys = 30.42 CPU) @ 16.44/s (n=500)
    medium: 33 wallclock secs (30.03 usr +  0.01 sys = 30.04 CPU) @ 16.64/s (n=500)
ridiculous: 187 wallclock secs (159.85 usr + 18.47 sys = 178.32 CPU) @  2.80/s (n=500)
     short: 30 wallclock secs (30.09 usr +  0.02 sys = 30.11 CPU) @ 16.61/s (n=500)
             Rate ridiculous       huge       long      short     medium
ridiculous 2.80/s         --       -82%       -83%       -83%       -83%
huge       15.8/s       465%         --        -4%        -5%        -5%
long       16.4/s       486%         4%         --        -1%        -1%
short      16.6/s       492%         5%         1%         --        -0%
medium     16.6/s       494%         5%         1%         0%         --