multiprocessing deadlock
Gabriel Genellina
gagsl-py2 at yahoo.com.ar
Fri Oct 23 23:10:31 EDT 2009
En Thu, 22 Oct 2009 23:18:32 -0300, Brian Quinlan <brian at sweetapp.com>
escribió:
I don't like a few things in the code:
> def _do(i):
> print('Run:', i)
> q = multiprocessing.Queue()
> for j in range(30):
> q.put(i*30+j)
> processes = _make_some_processes(q)
>
> while not q.empty():
> pass
I'd use time.sleep(0.1) or something instead of this busy wait, but see
below.
> # The deadlock only occurs on Mac OS X and only when these lines
> # are commented out:
> # for p in processes:
> # p.join()
I don't know how multiprocessing deals with it, but if you don't join() a
process it may become a zombie, so it's probably better to always join
them. In that case I'd just remove the wait for q.empty() completely.
> for i in range(100):
> _do(i)
Those lines should be guarded with: if __name__ == '__main__':
I don't know if fixing those things will fix your problem, but at least
the code will look neater...
--
Gabriel Genellina
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