message: Measure the performance of the original placement to ensure that we preserve it
  in case the placer isn't given enough time to find a better solution.
diff: @@ -68,6 +68,16 @@ def PlaceGraph(metagraph,
  item = gitem.Item(optimized_metagraph)
  + # Measure the runtime achievable with the original placement.
  + try:
  + _, original_run_time, _ = cluster.MeasureCosts(item)
  + if verbose:
  + print("Runtime for original placement: " + str(original_run_time))
  + except errors.OpError as e:
  + if verbose:
  + print("Original placement isn't feasible: " + str(e))
  + original_run_time = hparams.failing_signal
  +
  if hparams is None:
  hparams = hierarchical_controller.hierarchical_controller_hparams()
  # We run with a single child
  @@ -98,7 +108,7 @@ def PlaceGraph(metagraph,
  print("Failed to run graph:" + str(e))
  run_time = hparams.failing_signal
  updated = model.update_reward(sess, run_time, verbose=verbose)
  - if updated:
  + if updated and run_time < original_run_time:
  if verbose:
  print("Found better placement, with runtime " + str(run_time))
  model.export_placement(metagraph)
  