use Benchmark 'cmpthese';

my %hash = ( key => 'value' );

cmpthese( -3, {
   with =>		sub {
	   delete $INC{strict.pm};
	   require 'strict.pm';
	   strict::import( 'refs' );
	   my $a = 1;
	   my $b = 2
	},
   without =>	sub {
	   $hash{key} = delete $hash{key};            
	   my $a = 1; my $b = 2
	},
} );

__END__
P:\test>P:\bin\perl.exe junk.pl8
           Rate    with without
with     7281/s      --    -71%
without 24851/s    241%      --