Benchmark subroutine argument strategies

benchmark_sub_args.pl

#!perl

# source: http://www.perlmonks.org/?node_id=575918

use warnings;
use strict;

use Benchmark;

timethese(1_000_000, {
  'use_shift' => sub { sub_with_shift(0..9) },
  'use_list' => sub { sub_with_list(0..9) },
  'use_direct' => sub { sub_with_direct(0..9) },
});

sub sub_with_shift
{
  my $sum = 0;
  while (@_)
  {
    $sum += shift;
  }
  $sum;
}

sub sub_with_list
{
  my(@a)=@_;
  my $sum = 0;
  $sum += $_
    for @a;
  $sum;
}

sub sub_with_direct
{
  my $sum = 0;
  $sum += $_
    for @_;
  $sum;
}

Results on my desktop:

$ perl benchmark_sub_args.pl 
Benchmark: timing 1000000 iterations of use_direct, use_list, use_shift...
use_direct:  0 wallclock secs ( 0.60 usr +  0.00 sys =  0.60 CPU) @ 1666666.67/s (n=1000000)
  use_list:  1 wallclock secs ( 0.93 usr +  0.00 sys =  0.93 CPU) @ 1075268.82/s (n=1000000)
 use_shift: -1 wallclock secs ( 0.63 usr +  0.00 sys =  0.63 CPU) @ 1587301.59/s (n=1000000)