在一个循环中运行相互依赖的两个线程

Question

我需要知道如何编写一个运行两个线程的程序： 1线程更新对象的位置（值） 2基于第一个线程的值在其中运行两个方法的线程 所有这些都是一个循环

这是我所拥有的当前代码，我想按照我的描述进行更改，而不是值来自valueList，activate（valueList）是一个包含几个较小方法的方法。如果你不介意的话，我想举个例子来解决这个。谢谢在

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，线程并不能真正解决您的问题。特别是因为Python代码受Global Interpreter Lock的约束，这基本上意味着只有在代码是IO绑定的情况下（从磁盘读取大文件，等待慢速网络连接等），该编码才有帮助。如果您的程序受CPU限制，并且您真的想利用并行处理，multiprocessing是最好的选择。对于多处理，您可以牺牲一些内存开销和一点延迟（在创建进程时以及在进程间通信期间）来换取利用多核cpu的能力。在

为了避免并行处理对您的程序有用，或者您只是好奇，我提供以下代码示例。免责声明，我还没有尝试过导入这个模块，所以考虑一下它是伪代码。在

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()