gistfile1.pl

#!perl -w
use strict;
use Benchmark qw(:all);
use Sub::Call::Tail;

no warnings 'recursion';

sub rec_sum {
	if ( $_[0] == 0 ) {
		return 0;
	} else {
		return 1 + rec_sum($_[0]-1);
	}
}

sub sum {
	if ( $_[0] == 0 ) {
		return $_[1];
	} else {
		sum( $_[0] - 1, $_[1] + 1 );
	}
}

sub tail_sum {
	if ( $_[0] == 0 ) {
		return $_[1];
	} else {
		tail tail_sum( $_[0] - 1, $_[1] + 1 );
	}
}

sub goto_sum {
	if ( $_[0] == 0 ) {
		return $_[1];
	} else {
		@_ = ( $_[0] - 1, $_[1] + 1 );
		goto &goto_sum;
	}
}


foreach my $n ( map { 10 ** $_ } 0 .. 6 ) {
	print "testing sum($n)...\n";

	cmpthese -5 => {
		tail => sub{
			tail_sum($n, 0);
		},
		goto => sub{
			goto_sum($n, 0);
		},
		rec_accum => sub{
			sum($n, 0);
		},
		rec => sub {
			rec_sum($n);
		},
	};

	print "\n";
}

gistfile2.txt

testing sum(1)...
              Rate      goto      tail rec_accum       rec
goto      472421/s        --      -45%      -47%      -50%
tail      854544/s       81%        --       -5%      -10%
rec_accum 896098/s       90%        5%        --       -6%
rec       953999/s      102%       12%        6%        --

testing sum(10)...
              Rate      goto      tail       rec rec_accum
goto       74387/s        --      -48%      -50%      -51%
tail      141738/s       91%        --       -4%       -6%
rec       147540/s       98%        4%        --       -2%
rec_accum 150404/s      102%        6%        2%        --

testing sum(100)...
             Rate      goto      tail       rec rec_accum
goto       7933/s        --      -48%      -49%      -51%
tail      15228/s       92%        --       -2%       -5%
rec       15552/s       96%        2%        --       -3%
rec_accum 16105/s      103%        6%        4%        --

testing sum(1000)...
            Rate      goto      tail       rec rec_accum
goto       793/s        --      -49%      -49%      -52%
tail      1555/s       96%        --       -0%       -5%
rec       1559/s       97%        0%        --       -5%
rec_accum 1634/s      106%        5%        5%        --

testing sum(10000)...
            Rate      goto       rec rec_accum      tail
goto      78.3/s        --      -41%      -44%      -49%
rec        132/s       68%        --       -5%      -14%
rec_accum  140/s       78%        6%        --       -9%
tail       153/s       95%       16%        9%        --

testing sum(100000)...
            Rate      goto       rec rec_accum      tail
goto      7.71/s        --      -39%      -44%      -50%
rec       12.7/s       64%        --       -8%      -17%
rec_accum 13.7/s       78%        8%        --      -10%
tail      15.3/s       98%       20%       11%        --

testing sum(1000000)...
             Rate      goto       rec rec_accum      tail
goto      0.783/s        --      -36%      -42%      -48%
rec        1.22/s       55%        --      -10%      -19%
rec_accum  1.35/s       72%       11%        --      -10%
tail       1.50/s       92%       24%       12%        --