my $preAllocDummy = 5000;

# Fake call in order to pre-allocate the array.
example();

# Real call.
example();

sub example {
   # Trying a subtle pre-allocation hack.  Supposedly the space
   # allocated for @array will be preserved for later calls.
   my @array;
   if ($preAllocDummy) {
      print "Trying to preallocate to max size $preAllocDummy\n";
      $#array = $preAllocDummy - 1;
      $preAllocDummy = 0;
      return;
   }

   # Push stuff on the array here.
}