线程加锁
作者:互联网
加锁的作用:
1、多个线程同时修改同一个全局变量时,确保不被CPU切片阻断
2、加锁会加长执行时间
import threading
import time
metalocA = threading.Lock()
# metalocB = threading.Lock
num = 0
def func1():
for i in range(1000000):
global num
metalocA.acquire()
num +=1
metalocA.release()
def func2():
for i in range(1000000):
global num
metalocA.acquire()
num +=1
metalocA.release()
def main():
t1 = threading.Thread(target=func1)
t2 = threading.Thread(target=func2)
s_time = time.time()
t1.start()
t2.start()
t1.join()
t2.join()
e_time = time.time()
print(e_time-s_time)
if __name__ == '__main__':
main()
print(num)
''''
不加锁:
0.1509230136871338
1261326
加锁:
0.4519648551940918
2000000
'''
标签:__,加锁,threading,num,线程,time,metalocA 来源: https://www.cnblogs.com/bigcoolcool/p/16184660.html