#!/usr/bin/perl

use Benchmark qw(:all);

my $count = 1000000;

timethese($count, {
  'Name1' => sub {
     my( $a, $b, $c, $d ) = qw( kookla fran and ollie );
     foreach ($a, $b, $c, $d) {
       tr/a-z/A-Z/;
     }
   },
   'Name2' => sub {
      my( $a, $b, $c, $d ) = qw( kookla fran and ollie );
      for my $i ($a, $b, $c, $d) {
        $i =~ tr/a-z/A-Z/;
      }
    },
});

##</code><code>##

Benchmark: timing 1000000 iterations of Name1, Name2...
     Name1: 15 wallclock secs (15.70 usr +  0.08 sys = 15.78 CPU) @ 63371.36/s (n=1000000)
     Name2: 15 wallclock secs (15.31 usr +  0.02 sys = 15.33 CPU) @ 65231.57/s (n=1000000)