Rate w=1 w=0
w=1 3003/ms  -- -1%
w=0 3032/ms  1%  --

       Rate w=1 w=0
w=1 3002/ms  -- -0%
w=0 3010/ms  0%  --

##</code><code>##

use strict;
use warnings;

use Benchmark qw( cmpthese );

my $OUTER = $ARGV[0] || -3;
my $INNER = $ARGV[1] || 1000;

# ----------------------------------------

my %tests = (
   'w=1' => <<'__EOI__',
      use warnings;
      $arg .= $arg;
__EOI__
   'w=0' => <<'__EOI__',
      no warnings;
      $arg .= $arg;
__EOI__
);

# ----------------------------------------

my %bench = map { $_ => "use strict;
                         use warnings;
                         our \$arg;
                         for (1..$INNER) {
                            $tests{$_};
                         }
                        "
                }
              keys %tests;

{
   local our $arg = '';
   cmpthese($OUTER, \%bench);
   print("\n");
   print("Multiply by $INNER to get real rate.\n");
}

##</code><code>##

        Rate sr=0 sr=1
sr=0 2751/ms   --  -0%
sr=1 2759/ms   0%   --

        Rate sr=1 sr=0
sr=1 2735/ms   --  -1%
sr=0 2754/ms   1%   --

##</code><code>##

use strict;
use warnings;

use Benchmark qw( cmpthese );

my $OUTER = $ARGV[0] || -3;
my $INNER = $ARGV[1] || 1000;

# ----------------------------------------

my %tests = (
   'sr=1' => <<'__EOI__',
      use strict;
      $arg .= $$ref;
__EOI__
   'sr=0' => <<'__EOI__',
      no strict;
      $arg .= $$ref;
__EOI__
);

# ----------------------------------------

my %bench = map { $_ => "use strict;
                         use warnings;
                         our \$arg;
                         our \$ref;
                         for (1..$INNER) {
                            $tests{$_};
                         }
                        "
                }
              keys %tests;

{
   local our $arg = '';
   local our $ref = \$arg;
   cmpthese($OUTER, \%bench);
   print("\n");
   print("Multiply by $INNER to get real rate.\n");
}