python避免死锁方法实例分析
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。
