#!/usr/bin/perl
use strict;
use warnings;

use Benchmark qw/cmpthese/;

print "== Single subroutine argument ==\n";

sub b1_shift  { my $x = shift; $x . ''; }
sub b1_list   { my ($x) = @_;  $x . ''; }
sub b1_direct { $_[0] . ''; }

cmpthese( -5, {
    'shift'           => sub { b1_shift ('X' x rand 5000) },
    'list assignment' => sub { b1_list  ('X' x rand 5000) },
    'direct'          => sub { b1_direct('X' x rand 5000) }
});

print "== Two subroutine arguments ==\n";

sub b2_shift  { my $x = shift; my $y = shift; $x . $y; }
sub b2_list   { my ($x, $y) = @_;  $x . $y; }
sub b2_direct { $_[0] . $_[1]; }

cmpthese( -5, {
    'shift'           => sub { b2_shift ('X' x rand 5000, 'Y' x rand 5000) },
    'list assignment' => sub { b2_list  ('X' x rand 5000, 'Y' x rand 5000) },
    'direct'          => sub { b2_direct('X' x rand 5000, 'Y' x rand 5000) }
});


__END__
== Single subroutine argument ==
Benchmark: running direct, list assignment, shift, each for at least 5 CPU seconds...
    direct:  5 wallclock secs ( 5.10 usr +  0.02 sys =  5.12 CPU) @ 110247.85/s (n=564469)
list assignment:  5 wallclock secs ( 5.14 usr +  0.03 sys =  5.17 CPU) @ 89861.90/s (n=464586)
     shift:  6 wallclock secs ( 5.72 usr +  0.03 sys =  5.75 CPU) @ 70120.00/s (n=403190)
                    Rate           shift list assignment          direct
shift            70120/s              --            -22%            -36%
list assignment  89862/s             28%              --            -18%
direct          110248/s             57%             23%              --
== Two subroutine arguments ==
Benchmark: running direct, list assignment, shift, each for at least 5 CPU seconds...
    direct:  5 wallclock secs ( 5.46 usr +  0.00 sys =  5.46 CPU) @ 57434.25/s (n=313591)
list assignment:  6 wallclock secs ( 5.30 usr +  0.02 sys =  5.32 CPU) @ 46535.53/s (n=247569)
     shift:  6 wallclock secs ( 5.00 usr +  0.01 sys =  5.01 CPU) @ 42526.95/s (n=213060)
                   Rate           shift list assignment          direct
shift           42527/s              --             -9%            -26%
list assignment 46536/s              9%              --            -19%
direct          57434/s             35%             23%              --