【Python】[进程和线程]多进程，多线程，ThreadLocal，进程VS.线程，分布式进程

1、多进程，multiprocessing模块，
   进程间的通信：Queue[队列],Pipes[管子]
2、多线程，
   注意：线程公用变量，混乱
   解决方法Lock：因为只有一个锁，所以当要执行统一个函数的时候，只有在解锁的前提下才能

执行。

balance = 0
lock = threading.Lock()

def run_thread(n):
    for i in range(100000):
        # 先要获取锁:
        lock.acquire()
        try:
            # 放心地改吧:
            change_it(n)
        finally:
            # 改完了一定要释放锁:
            lock.release()

3、ThreadLocal  一个全局变量。
看代码：

import threading

# 创建全局ThreadLocal对象:
local_school = threading.local()

def process_student():
    # 获取当前线程关联的student:
    std = local_school.student
    print('Hello, %s (in %s)' % (std, threading.current_thread().name))

def process_thread(name):
    # 绑定ThreadLocal的student:
    local_school.student = name
    process_student()

t1 = threading.Thread(target= process_thread, args=('Alice',), name='Thread-A')
t2 = threading.Thread(target= process_thread, args=('Bob',), name='Thread-B')
t1.start()
t2.start()
t1.join()
t2.join()

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