use Benchmark 'cmpthese';

our $a=1;
our $b=2;
our $tmp;

print "Dynamic variables, swap benchmark.\n";
cmpthese -10, {standard => '$::tmp=$::a; $::a=$::b; $::b=$tmp;',
              list     => '($::a,$::b)=($::b,$::a)'
             };
print "Lexical variables, swap benchmark.\n";
cmpthese -10, {
	          standard_my     => sub{my $x=1;my $y=2; my $z =$x; $x=$y; $y=$z},
	          standard_local  => sub{my $x=1;my $y=2; local $_=$x; $x=$y; $y=$_},
	          standard_global => sub{my $x=1;my $y=2; $_=$x; $x=$y; $y=$_},
              list            => sub{my $x=1;my $y=2; ($x,$y)=($y,$x)},
             };
__END__
Dynamic variables, swap benchmark.
Benchmark: running list, standard, each for at least 10 CPU seconds...
      list: 11 wallclock secs (10.39 usr +  0.00 sys = 10.39 CPU) @ 664534.94/s (n=6904518)
  standard: 11 wallclock secs (10.84 usr +  0.00 sys = 10.84 CPU) @ 983324.54/s (n=10662188)
             Rate     list standard
list     664535/s       --     -32%
standard 983325/s      48%       --
Lexical variables, swap benchmark.
Benchmark: running list, standard_global, standard_local, standard_my, 
  each for at least 10 CPU seconds...
      list: 10 wallclock secs (10.13 usr +  0.00 sys = 10.13 CPU) @ 404027.75/s (n=4090781)
standard_global:
  9 wallclock secs (10.05 usr +  0.00 sys = 10.05 CPU) @ 484686.67/s (n=4869647)
standard_local: 
 10 wallclock secs (10.03 usr +  0.00 sys = 10.03 CPU) @ 402621.17/s (n=4038693)
standard_my: 
 10 wallclock secs (10.80 usr +  0.00 sys = 10.80 CPU) @ 503630.27/s (n=5437696)

                    Rate standard_local         list standard_global standard_my
standard_local  402621/s             --          -0%            -17%        -20%
list            404028/s             0%           --            -17%        -20%
standard_global 484687/s            20%          20%              --         -4%
standard_my     503630/s            25%          25%              4%          --