use strict; 
use warnings; 
use Parallell::ForkManager; 
 
 
my $fork = Parallell::ForkManager->new(4); #number of max forks 
 
 
for(0..1000){ 
  my $pid = $fork->start and next; 
 
  #work here for the forks to do; 
  print "PID: $pid ::: WORK: $_ \n"; 
 
  $fork->finish; 
} 
$fork->wait_all_children;