[Python-Dev] Add an optional timeout to lock operations

[Antoine Pitrou]

Hello,

> > I've submitted a patch (*) to add an optional timeout to locking
> > operations (Lock.acquire() etc.). Since it's a pretty basic
> > functionality, I would like to know if there was any good reason for
> > not doing it.
> 
> I always assumed it was because as a least-common-denominator set of
> functionality, some platforms didn't have the necessary support.

Guido's answer says so indeed. Now py3k only needs to support POSIX and Windows
(and, provided Andrew MacIntyre maintains the port, OS/2), which both have
standard support for waiting-with-timeout.

> Providing the discussion on this ends up with the an implementation
> being accepted, I'd absolutely love to see this then leveraged by
> threading.Condition.wait() rather rather than the current
> poll-with-timed-sleep approach.

Agreed. The current patch (as proposed on http://bugs.python.org/issue7316)
includes exactly that.
Poll-with-timed-sleep is especially sub-optimal on laptops where short but
frequent wakeups can cause a significant decrease in battery life.
(the Linux community has been chasing this using powertop:
http://www.lesswatts.org/projects/powertop/)

Feel free to test or review if you're interested.

Regards

Antoine.