#!/usr/bin/perl
use strict;
use warnings;
use Time::HiRes qw(time);

my $num = 3_000_000;
my $str = 'x'x$num . 'reg exp' . 'x'x$num; 

my $start = time;

my $res = $str =~ m/reg exp/;

print time - $start, $/;

$start = time;

my $idx = index $str, 'reg exp';

print time - $start, $/;
__END__
0.0114099979400635
0.011760950088501

##</code><code>##

         Rate REGEX INDEX
REGEX 87061/s    --   -2%
INDEX 88494/s    2%    --