def StopTiming(self, profile_name):
    """Stops timing CPU time.

    Args:
      profile_name (str): name of the profile to sample.
    """
    measurements = self._profile_measurements.get(profile_name)
    if measurements:
      measurements.SampleStop()

      sample = '{0:f}\t{1:s}\t{2:f}\n'.format(
          measurements.start_sample_time, profile_name,
          measurements.total_cpu_time)
      self._WritesString(sample)