運行兩個相互依賴的線程

Question

我需要知道如何編寫運行兩個線程的程序： 1.一個線程更新對象的位置（值） 2.一個線程根據第一個線程的值運行兩種方法 所有這一切都在一個循環中

這是當前的代碼，我想要更改，因爲我描述過，而不是值的形式valueList和activate（valueList）是一個包含幾個較小方法的方法。如果你不介意，我很想有一個例子來解決this.Thanks

client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
client_socket.connect(('59.191.193.42',5555)) 


screenw = 0 
screenh = 0 
while 1: 
    client_socket.send("loc\n") 
    data = client_socket.recv(8192) 
    valueList = data.split() 

    if (not(valueList[-1] == "eom" and valueList[0] == "start")): 
     #print "continuing.." 
      continue 

     if(screenw != int(valueList[2])): 
      screenw = int(valueList[2]) 
      screenh = int(valueList[3]) 

    activate(valueList) 

Answer 1

正如其他人所指出的那樣，它看起來並不像線程實際上是要解決你的問題。特別是因爲Python代碼受限於Global Interpreter Lock，這基本上意味着如果您的代碼是IO-綁定的（從磁盤讀取大文件，等待慢速網絡連接等），則只會幫助您執行代碼。如果您的程序受CPU限制，並且您確實想要利用並行處理，則需要使用multiprocessing。通過多處理，您可以交換一些內存開銷和一點延遲（在進程創建時以及進程間通信期間），以便利用多核CPU。

就在平行處理確實對你的程序有用，或者你只是好奇而已，我提出下面的代碼示例。免責聲明，我沒有試過導入這個模塊，所以認爲它是僞代碼。

import socket 
from multiprocessing import Process, Queue, Value 
from ctypes import c_bool 

HOST = '198.51.100.0' 
PORT = 8080 

# This function will be run in a child process 
def update_proc(data_queue, update_queue, quit_flag): 
    while not quit_flag.value: 
     data = data_queue.get() 
     # do something with the data... 
     update_queue.put(data) 
    print "Closing child update process" 

# This function will be run in a child process 
def activate_proc(update_queue, quit_flag): 
    while not quit_flag.value: 
     data = update_queue.get() 
     # do something with the data... 
    print "Closing child activate process" 

# main process begins execution here, if module is run from the terminal 
if __name__ == "__main__": 
    # Connect to remote host over TCP 
    client = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
    client.connect((HOST,PORT)) 

    # Set up a Queue to pass data to the update process, and another one 
    # for the two children to communicate 
    data_queue = Queue() 
    update_queue = Queue() 

    # The quit_flag Value is a *very* primitive way to signal the child 
    # processes to quit. I'm sure there are better ways to do this, but I'm 
    # tired and can't think of any right now. 
    quit_flag = Value(c_bool, False) 

    # Create two child processes, pass a reference to the Queue to each 
    update = Process(target=update_proc, args=(data_queue, update_queue, quit_flag)) 
    activate = Process(target=activate_proc, args=(update_queue, quit_flag)) 

    update.start() 
    activate.start() 

    # Read data from the TCP socket, push it onto the data_queue 
    while True: 
     client.sendall("loc\n") 
     data = client.recv(8192) 
     if not data: 
      print "network connection closed by client" 
      break 
     data_queue.put(data) 

    # Join with child processes before closing 
    print "All done, closing child processes" 
    update.join() 
    activate.join()