use Benchmark 'cmpthese';

my $a = 'foo bar doz' x 100;
$a .= ' hello '.$a;

my $sub = sub {
  /\bhello\b/; /\bhello\b/; /\bhello\b/; /\bhello\b/;
  /\bhello\b/; /\bhello\b/; /\bhello\b/; /\bhello\b/;
};

cmpthese(-3, { loop => sub {
                 for (($a) x 10) {
                   for my $i (1..8) {
                     /\bhello\b/;
                   }
                 }
               },
               sub => sub {
                 for (($a) x 10) {
                   $sub->()
                 }
               },
               inline => sub {
                 for (($a) x 10) {
                   /\bhello\b/; /\bhello\b/; /\bhello\b/; /\bhello\b/;
                   /\bhello\b/; /\bhello\b/; /\bhello\b/; /\bhello\b/;
                 }
               }