python profiling in pants snippet. Install guppy into the virtual env (env/bin/pip install guppy).

pants_exe._run()

def _run(exiter):
  # We want to present warnings to the user, set this up early to ensure all warnings are seen.
  # The "default" action displays a warning for a particular file and line number exactly once.
  # See https://docs.python.org/2/library/warnings.html#the-warnings-filter for the complete action
  # list.
  warnings.simplefilter('default')

  # Bootstrap options and logging.
  options, build_config = OptionsInitializer().setup()

  # Apply exiter options.
  exiter.apply_options(options)

  # Launch RunTracker as early as possible (just after Subsystem options are initialized).
  run_tracker, reporting = ReportingInitializer().setup()

  # Determine the build root dir.
  root_dir = get_buildroot()

  # Setup and run GoalRunner.

  try:
    from guppy import hpy
    h = hpy()
    before = h.heap()
    goal_runner = GoalRunner.Factory(root_dir, options, build_config, run_tracker, reporting).setup()
    result = goal_runner.run()
  except KeyboardInterrupt:
    after = h.heap()
    pants_heap = after - before
    print("!!!!!!!      Starting a trace   !!!!!!!!!!!!!!")
    import pdb; pdb.set_trace()
    print("!!!!!!!      Ending a trace   !!!!!!!!!!!!!!")



  exiter.do_exit(result)