线程锁，递归锁

# from threading import Thread,Lock,current_thread
# import os ,time
# def task():
#     global n
#     print('%s is running'%current_thread().getName())
#     temp=n
#     time.sleep(0.5)
#     n=temp-1
# if __name__=='__main__':
#     n=100
#     lock=Lock()
#     threads_list=[]
#     start_time=time.time()
#     for i in range(100):
#         t=Thread(target=task)
#         threads_list.append(t)
#         t.start()
#     for t in threads_list:
#         t.join()
#     stop_time=time.time()
#     print("zhu%s:%s"%(stop_time-start_time,n))
# Thread-99 is running
# Thread-100 is running
# zhu0.5460002422332764:99
无锁，执行时间最短，但不能保证数据正确性（在同一时间所有进程都拿到了初始值100，然后开始计算）



# from threading import Thread,Lock,current_thread
# import os ,time
# def task(lock):
#     global n
#     print('%s is running'%current_thread().getName())  #lock 之前的代码可以先执行，然后等待别的线程释放锁
#     lock.acquire()
#     temp=n
#     time.sleep(0.5)
#     n=temp-1
#     lock.release()
# if __name__=='__main__':
#     n=100
#     lock=Lock()
#     thread_list=[]
#     start_time=time.time()
#     for i in range(100):
#         t=Thread(target=task,args=(lock,))
#         thread_list.append(t)
#         t.start()
#     for t in thread_list:
#         t.join()
#     stop_time=time.time()
#     print('zhu %s:%s'%(stop_time-start_time,n))
# Thread-96 is running
# Thread-97 is running
# Thread-98 is running
# Thread-99 is running
# Thread-100 is running
# zhu 50.00099992752075:0
加锁，效率变低，但数据呜呜
from threading import Thread,Lock,current_thread
import os ,time
def task():
    global n
    print('%s is running'%current_thread().getName())  #如果lock之前的代码很长，将会很费时间，每次都是一个一个从头执行，不能先执行
    # lock.acquire()
    temp=n
    time.sleep(0.5)
    n=temp-1
    # lock.release()
if __name__=='__main__':
    n=100
    start_time=time.time()
    for i in range(100):
        t=Thread(target=task)
        t.start()
        t.join()
    stop_time=time.time()
    print('zhu %s:%s'%(stop_time-start_time,n))

# Thread-95 is running
# Thread-96 is running
# Thread-97 is running
# Thread-98 is running
# Thread-99 is running
# Thread-100 is running
# zhu 50.01300024986267:0
p.start()后立即p.join(),等于串行，等于把所有的代码都执行一遍

 

from threading import Thread,Lock,RLock
import time
A=B=RLock()
#A=Lock()
#B=Lock()
class MyThread(Thread):
    def run(self):
        self.func1()
        self.func2()
    def func1(self):
        A.acquire()
        print("拿到A")
        B.acquire()
        print("拿到B")
        B.release()
        A.release()
    def func2(self):
        B.acquire()
        print("2拿到B")
        time.sleep(2)
        A.acquire()
        print("2拿到A")
        A.release()
        B.release()
if __name__=='__main__':
    for i in range(10):
        t=MyThread()
        t.start()

# 拿到A
# 拿到B
# 2拿到B,#等待A
# 拿到A  #等待


#Rlock
# 拿到A        
# 拿到B
# 2拿到B
# 2拿到A
# 拿到A
# 拿到B
# 2拿到B
# 2拿到A

一个线程拿到锁，counter加1,该线程内又碰到加锁的情况，则counter继续加1，这期间所有其他线程都只能等待，等待该线程释放所有锁，即counter递减到0为止