python避免死锁方法实例分析_Python

本文实例讲述了python避免死锁方法。分享给大家供大家参考。具体分析如下：

当两个或者更多的线程在等待资源的时候就会产生死锁，两个线程相互等待。
在本文实例中 thread1 等待thread2释放block , thread2等待thtead1释放ablock，

避免死锁的原则：

1. 一定要以一个固定的顺序来取得锁，这个列子中，意味着首先要取得alock, 然后再去block

2. 一定要按照与取得锁相反的顺序释放锁，这里，应该先释放block,然后是alock

									import threading ,time

									a = 5

									alock = threading.Lock()

									b = 5

									block = threading.Lock()

									def thread1calc():

									  print "thread1 acquiring lock a"

									  alock.acquire()

									  time.sleep(5)

									  print "thread1 acquiring lock b"

									  block.acquire()

									  a+=5

									  b+=5

									  print "thread1 releasing both locks"

									  block.release()

									  alock.release()

									def thread2calc():

									  print "thread2 acquiring lock b"

									  block.acquire()

									  time.sleep(5)

									  print "thread2 acquiring lock a"

									  alock.acquire()

									  time.sleep(5)

									  a+=10

									  b+=10

									  print "thread2 releasing both locks"

									  block.release()

									  alock.release()

									t = threading.Thread(target = thread1calc)

									t.setDaemon(1)

									t.start()

									t = threading.Thread(target = thread2calc)

									t.setDaemon(2)

									t.start()

									while 1:

									  time.sleep(300)

输出：

									thread1 acquiring lock a

									thread2 acquiring lock b

									thread1 acquiring lock b

									thread2 acquiring lock a

希望本文所述对大家的Python程序设计有所帮助。

python避免死锁方法实例分析

相关文章

热门资讯