#!perl

use strict;
use warnings;

use Benchmark qw(:all);

my $foo;

timethese('50000000', {
    'test_1' => sub { $foo = 1; },
    'test_2' => sub { my $bar = 1; },
});

1;

__END__

fred@fishman ~ $ perl scope.pl 
Benchmark: timing 10000000 iterations of test_1, test_2...
    test_1:  0 wallclock secs ( 1.03 usr +  0.01 sys =  1.04 CPU) @ 9615384.62/s (n=10000000)
    test_2:  2 wallclock secs ( 1.38 usr +  0.01 sys =  1.39 CPU) @ 7194244.60/s (n=10000000)


fred@fishman ~ $ perl scope.pl 
Benchmark: timing 50000000 iterations of test_1, test_2...
    test_1:  6 wallclock secs ( 5.19 usr +  0.01 sys =  5.20 CPU) @ 9615384.62/s (n=50000000)
    test_2:  6 wallclock secs ( 6.51 usr +  0.00 sys =  6.51 CPU) @ 7680491.55/s (n=50000000)