sample code snapshot:

sub f2 {
  my $ht_ref = shift;
  my %ht = %$ht_ref;
  print "some val = ", $ht{1}, "\n";
  %ht=();
  undef %ht;
}
sub f1 {
  my %ht=();
  my $i;
  for ($i=0; $i<0xfffff; $i++) {
    $ht{$i} = $i;
  }
  f2 (\%ht);
  %ht=();
  undef %ht;
}

f1();
while (1) {
  # sleep here and monitor the memory.  memory
  # does'nt seem to come down :((
  sleep (5);
}