gclient_utils.py 文件源码

def NumLocalCpus():
  """Returns the number of processors.

  multiprocessing.cpu_count() is permitted to raise NotImplementedError, and
  is known to do this on some Windows systems and OSX 10.6. If we can't get the
  CPU count, we will fall back to '1'.
  """
  # Surround the entire thing in try/except; no failure here should stop gclient
  # from working.
  try:
    # Use multiprocessing to get CPU count. This may raise
    # NotImplementedError.
    try:
      import multiprocessing
      return multiprocessing.cpu_count()
    except NotImplementedError:  # pylint: disable=bare-except
      # (UNIX) Query 'os.sysconf'.
      # pylint: disable=no-member
      if hasattr(os, 'sysconf') and 'SC_NPROCESSORS_ONLN' in os.sysconf_names:
        return int(os.sysconf('SC_NPROCESSORS_ONLN'))

      # (Windows) Query 'NUMBER_OF_PROCESSORS' environment variable.
      if 'NUMBER_OF_PROCESSORS' in os.environ:
        return int(os.environ['NUMBER_OF_PROCESSORS'])
  except Exception as e:
    logging.exception("Exception raised while probing CPU count: %s", e)

  logging.debug('Failed to get CPU count. Defaulting to 1.')
  return 1