use Benchmark 'cmpthese';

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

cmpthese( -10, {
   with =>		sub {delete $INC{strict.pm}; use strict '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 without    with
without  25587/s      --    -79%
with    121330/s    374%      --