#!/usr/bin/perl
use strict;
use warnings;
use Benchmark ('cmpthese');
my $dqv = 0;
my $sqv = 0;

cmpthese(1000000, {
                 double => \&dq,
                 single => \&sq,
                });

sub dq {
  $dqv++;
  my $str = "see $dqv run                                                                                     and $dqv";
}

sub sq {
  $sqv++;
  my $str = 'see '.$dqv.' run                                                                                     and '.$dqv;
}

##</code><code>##

            Rate double single
double  943396/s     --   -37%
single 1492537/s    58%     --