use Benchmark 'cmpthese';

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

cmpthese( -3, {
   with =>	q[
	   BEGIN{ delete $INC{strict.pm}; use strict 'refs' }
	   my $a = 1; my $b = 2
	],
   without => q[
	   BEGIN{ $hash{key} = delete $hash{key} }
	   my $a = 1; my $b = 2
	],
} );

__END__
P:\test>P:\bin\perl.exe junk.pl8
            Rate without    with
without 374581/s      --     -0%
with    375658/s      0%      --