parallel_loop.py 文件源码

def __init__(self, j=os.cpu_count(), max_utilization=100):
        """
        Initialize a parallel loop object.

        :param j: The maximum number of parallel jobs.
        :param max_utilization: The maximum CPU utilization. Above this no more new jobs
                                will be started.
        """
        self._j = j
        self._max_utilization = max_utilization
        # This gets initialized to 0, may be set to 1 anytime, but must not be reset to 0 ever;
        # thus, no locking is needed when accessing
        self._break = multiprocessing.sharedctypes.Value('i', 0, lock=False)
        self._lock = multiprocessing.Condition()
        self._slots = multiprocessing.sharedctypes.Array('i', j, lock=False)
        psutil.cpu_percent(None)

    # Beware! this is running in a new process now. state is shared with fork,
    # but only changes to shared objects will be visible in parent.