#!/usr/bin/perl

# ->resume is not exactly cheap (it saves/restores a LOT
# of global variables), but shouldn't be slow. just to show
# how fast it is, this little proggie compares a normal subroutine
# call with two calls of transfer in a loop.

use Coro;
use Benchmark;

sub a($) { }

$a = bless {}, main::;

sub b {
   my ($self) = shift;
   $self->{b} = shift if @_;
   $self->{b};
}

$b = async {
   # do a little unrolling...
   while() {
      cede; cede; cede; cede; cede;
      cede; cede; cede; cede; cede;
   }
};

cede;

*transfer = \&Coro::State::transfer;

sub doit0 {
   while() {
      # some unrolling here as well..
      transfer($c0, $main); transfer($c0, $main);
      transfer($c0, $main); transfer($c0, $main);
      transfer($c0, $main); transfer($c0, $main);
      transfer($c0, $main); transfer($c0, $main);
   }
}

sub doit1 {
   while() {
      # some unrolling here as well..
      transfer($c1, $main); transfer($c1, $main);
      transfer($c1, $main); transfer($c1, $main);
      transfer($c1, $main); transfer($c1, $main);
      transfer($c1, $main); transfer($c1, $main);
   }
}

$c0 = new Coro::State sub {
   doit0(1,2,3,4,5,6,7,8,9);
};

$c1 = new Coro::State sub {
   doit1(1,2,3,4,5,6,7,8,9);
};

#$c0->save (0);
#$c1->save (-1);

#Coro::State::enable_times 1;
#use Coro::Debug; Coro::Debug::command "ps";#d#
#(async {
   $main = $Coro::current;

   transfer($main, $c0);
   transfer($main, $c1);

   timethese 5000000, {
      function  => 'a(5); a(6)',
      method    => '$a->b(5); $a->b(6)',
      cede      => 'cede',
      transfer0 => 'transfer($main, $c0)',
      transfer1 => 'transfer($main, $c1)',
   };
#})->join;
#use Coro::Debug; Coro::Debug::command "ps";#d#