暂停两个Python线程，而第三个线程填充（带锁？）

暂停两个Python线程，而第三个线程填充（带锁？）

如何使用threading.Events：

import threadingimport timeimport logginglogger=logging.getLogger(__name__)def f(resume,is_waiting,name):    while True:        if not resume.is_set(): is_waiting.set() logger.debug('{n} pausing...'.format(n=name)) resume.wait() is_waiting.clear()        logger.info(name)        time.sleep(1)def h(resume,waiters):    while True:        logger.debug('halt')         resume.clear()        for i,w in enumerate(waiters): logger.debug('{i}: wait for worker to pause'.format(i=i)) w.wait()        logger.info('h begin')        time.sleep(2)        logger.info('h end')     logger.debug('resume')        resume.set()        time.sleep(5)logging.basicConfig(level=logging.DEBUG,         format='[%(asctime)s %(threadName)s] %(message)s',         datefmt='%H:%M:%S')# set means resume; clear means haltresume = threading.Event()resume.set()waiters=[]for name in 'fg':    is_waiting=threading.Event()    waiters.append(is_waiting)    threading.Thread(target=f,args=(resume,is_waiting,name)).start()    threading.Thread(target=h,args=(resume,waiters)).start()

产量

[07:28:55 Thread-1] f[07:28:55 Thread-2] g[07:28:55 Thread-3] halt[07:28:55 Thread-3] 0: wait for worker to pause[07:28:56 Thread-1] f pausing...[07:28:56 Thread-2] g pausing...[07:28:56 Thread-3] 1: wait for worker to pause[07:28:56 Thread-3] h begin[07:28:58 Thread-3] h end[07:28:58 Thread-3] resume[07:28:58 Thread-1] f[07:28:58 Thread-2] g[07:28:59 Thread-1] f[07:28:59 Thread-2] g[07:29:00 Thread-1] f[07:29:00 Thread-2] g[07:29:01 Thread-1] f[07:29:01 Thread-2] g[07:29:02 Thread-1] f[07:29:02 Thread-2] g[07:29:03 Thread-3] halt

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（针对评论中的问题）此代码尝试测量

h

-thread从其他工作线程获取每个锁所花费的时间。

似乎表明，即使

h

正在等待获取锁，另一个工作线程也可能以相当高的概率释放并重新获取锁。没有优先权

h

只是因为它等待了更长的时间。

David
Beazley在PyCon上介绍了有关线程和GIL的问题。这是幻灯片的pdf格式。这是一本引人入胜的书，也可能有助于解释这一点。

import threadingimport timeimport logginglogger=logging.getLogger(__name__)def f(lock,n):    while True:        with lock: logger.info(n) time.sleep(1)def h(locks):    while True:        t=time.time()        for n,lock in enumerate(locks): lock.acquire() t2=time.time() logger.info('h acquired {n}: {d}'.format(n=n,d=t2-t)) t=t2        t2=time.time()        logger.info('h {d}'.format(d=t2-t))        t=t2        for lock in locks: lock.release()        time.sleep(5)logging.basicConfig(level=logging.DEBUG,         format='[%(asctime)s %(threadName)s] %(message)s',         datefmt='%H:%M:%S')locks=[]N=5for n in range(N):    lock=threading.Lock()    locks.append(lock)    t=threading.Thread(target=f,args=(lock,n))    t.start()threading.Thread(target=h,args=(locks,)).start()