use MCE::Loop max_workers => 4, chunk_size => 1;

   ## non-chunking takes 2m18s to complete

   mce_loop {
      MCE->say($_);

   } 1..4_000_000;


##</code><code>##

   use MCE::Loop max_workers => 4, chunk_size => 'auto';

   ## chunking takes 0m12s to complete (IPC becomes 11.5x faster)

   mce_loop {
      my ($mce, $chunk_ref, $chunk_id) = @_;

      my @o; for (@{ $chunk_ref }) {
         push @o, $_;
      }
      MCE->say(@o);

   } 1..4_000_000;


##</code><code>##

   use MCE::Loop max_workers => 4, chunk_size => 'auto';

   ## processing a file directly (mce_loop_f) takes 0m11.7s

   mce_loop_f {
      my ($mce, $chunk_ref, $chunk_id) = @_;
      chomp @{ $chunk_ref };

      my @o; for (@{ $chunk_ref }) {
         push @o, $_;
      }
      MCE->say(@o);

   } '/path/to/four_million_rows.txt';


##</code><code>##

   ## array non-chunking...:  1m54.467s
   ## array auto-chunking..:  0m 0.843s   136x
   ## file  auto-chunking..:  0m 0.467s   245x

##</code><code>##

   ## array non-chunking...:  1m 5.458s
   ## array auto-chunking..:  0m 0.821s    80x
   ## file  auto-chunking..:  0m 0.411s   159x

##</code><code>##

   mce_loop_f {
      MCE->last;    # immediately leaves the block and input
      ... 
   } '/path/to/four_million_rows.txt';


##</code><code>##

   ## array non-chunking...:  1m 5.384s
   ## array auto-chunking..:  0m 0.747s    88x
   ## file  auto-chunking..:  0m 0.337s   194x