use Time::HiRes qw(gettimeofday tv_interval);
 
  my $start_time = [ gettimeofday ];
  sub_that_takes_a_teeny_bit_of_time();
  my $end_time = [ gettimeofday ];
  my $elapsed = tv_interval($start_time,$end_time);
  
  print "The sub took $elapsed seconds."