bench.pl

#!perl
use strict;
use warnings;

use Dumbbench;
use Time::HiRes qw( gettimeofday );

my $bench = Dumbbench->new(
    target_rel_precision => 0.005,    # seek ~0.5%
    initial_runs         => 20,       # the higher the more reliable
);

my $iruns = 1e5;
$bench->add_instances(
    Dumbbench::Instance::PerlSub->new(
        name => "noop",
        code => sub {
            for ( 1 .. $iruns ) {
                my $value = [ $_, $_ ];
                defined $value and next;
            }
        }
    ),
    Dumbbench::Instance::PerlSub->new(
        name => "gettimeofday",
        code => sub {
            for ( 1 .. $iruns ) {
                my $value = [gettimeofday];
                defined $value and next;
            }
        }
    )
);
$bench->run;
$bench->report;

hand-math.txt

noop:         3.6766e-02  ±  2.1e-05  per 1e5 its
gettimeofday 15.1750e-02  ± 28.0e-05  per 1e5 its

            = 11.4984e-02  per 1e5 its
            = 11.4984e-07  per it

out.txt

noop: Ran 31 iterations (11 outliers).
noop: Rounded run time per iteration: 3.6766e-02 +/- 2.1e-05 (0.1%)
gettimeofday: Ran 28 iterations (8 outliers).
gettimeofday: Rounded run time per iteration: 1.5175e-01 +/- 2.8e-04 (0.2%)