async.py 文件源码

def run(self):
        cls = MultiprocessRunner
        started = False
        if self not in cls.running_instances:
            cls.running_instances.add(self)
        if not cls.executor_instance:
            self.executor = futures.ProcessPoolExecutor(
                max_workers=self.max_workers)
            cls.executor_instance = self
            started = True
        elif not cls.executor_instance.running:
            cls.executor_instance.executor = futures.ProcessPoolExecutor(
                max_workers=self.max_workers)
            started = True
        self.executor = cls.executor_instance.executor
        if started:
            workers = self.executor._max_workers # Derived from cpu_count()
            logging.debug(
                _("Starting the MultiprocessRunner executor with %s worker "
                "processes.") % workers)