#!/usr/bin/perl -w

use strict;
use warnings 'all';
use POSIX 'ceil';
use forks;
use forks::shared;

my @unprocessed = get_data();
my @processed : shared = ( );

my $total_records = scalar(@unprocessed);
my $max_workers = 5;
my $chunk_size = ceil($total_records / $max_workers);

while( my @chunk = splice(@unprocessed, 0, $chunk_size) )
{
  threads->create(\&process_chunk, \@chunk);
}# end while()

# Keep an eye on our progress:
threads->create(sub {
  my $finished = scalar(@processed);
  print STDERR "\r$finished/$total_records";
});

# Now wait for everyone to finish...
$_->join foreach threads->list;


# Process a chunk of data:
sub process_chunk
{
  my @chunk = @_;
  while( my $item = shift(@chunk) )
  {
    # Do something with $_, then...

    # Supposing $item has an id...
    lock(@processed);
    push @processed, $item->id;
  }# end while()
}# end process_chunk()