ryu Address already in use

[root@kunpeng82 app]# ryu-manager simple_switch.py
loading app simple_switch.py
loading app ryu.controller.ofp_handler
instantiating app simple_switch.py of SimpleSwitch
instantiating app ryu.controller.ofp_handler of OFPHandler
hub: uncaught exception: Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/ryu/lib/hub.py", line 60, in _launch
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/ryu/controller/controller.py", line 153, in __call__
    self.ofp_ssl_listen_port)
  File "/usr/local/lib/python3.6/site-packages/ryu/controller/controller.py", line 202, in server_loop
    datapath_connection_factory)
  File "/usr/local/lib/python3.6/site-packages/ryu/lib/hub.py", line 127, in __init__
    self.server = eventlet.listen(listen_info)
  File "/usr/local/lib/python3.6/site-packages/eventlet/convenience.py", line 78, in listen
    sock.bind(addr)
OSError: [Errno 98] Address already in use

kill -9 57495
ryu-manager --ofp-tcp-listen-port 5555 -verbose
把端口号5555分配给ryu