Python线程同步的几种方法

# -*-coding:utf-8 -*-
#<征服python--语言基础与典型用例>P153
#简单线程同步，加锁
import threading
import time
class mythread(threading.Thread):
    def __init__(self,threadname):
        threading.Thread.__init__(self, name = threadname)
    def run(self):
        global x
        lock.acquire()
        for i in range(3):
            x = x + 1
        time.sleep(2)
        print x
        lock.release()
lock = threading.RLock()
t1 = []
for i in range(10):
    t = mythread(str(i))
    t1.append(t)
x = 0
for i in t1:
    i.start()
    
'''
output:
3
6
9
12
15
18
21
24
27
30
""

如果不加锁，则会如下结果:

output
30
30
30
30
30
30
30
30
30
30
'''