Message 296593 - Python tracker

Message296593

Author	vstinner
Recipients	vstinner
Date	2017-06-21.22:38:43
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1498084723.44.0.281135325364.issue30727@psf.upfronthosting.co.za>
In-reply-to

Content
test.test_threading.ConditionTests.test_notify() tests the threading._Condition. threading._Condition uses internally a threading._RLock. threading._RLock uses an internal lock created with thread.allocate_lock(). thread.allocate_lock() calls internally PyThread_allocate_lock(). On my Linux (Fedora 25) and FreeBSD (FreeBSD 11 VM) machines, PyThread_allocate_lock() calls sem_init(): POSIX pthread semaphores. In Python 3, RLock was implemented in C for speed (the new Python 3.0 io module was slow because of RLock performance): see bpo-3001. I know at least one race condition in Python 2.7 RLock: bpo-13697, RLock bug with signals.

Content

test.test_threading.ConditionTests.test_notify() tests the threading._Condition.

threading._Condition uses internally a threading._RLock.

threading._RLock uses an internal lock created with thread.allocate_lock().

thread.allocate_lock() calls internally PyThread_allocate_lock(). On my Linux (Fedora 25) and FreeBSD (FreeBSD 11 VM) machines, PyThread_allocate_lock() calls sem_init(): POSIX pthread semaphores.

In Python 3, RLock was implemented in C for speed (the new Python 3.0 io module was slow because of RLock performance): see bpo-3001.

I know at least one race condition in Python 2.7 RLock: bpo-13697, RLock bug with signals.

History
Date	User	Action	Args
2017-06-21 22:38:43	vstinner	set	recipients: + vstinner
2017-06-21 22:38:43	vstinner	set	messageid: <1498084723.44.0.281135325364.issue30727@psf.upfronthosting.co.za>
2017-06-21 22:38:43	vstinner	link	issue30727 messages
2017-06-21 22:38:43	vstinner	create