| msg131995 - (view) |
Author: Antoine Pitrou (pitrou) *  |
Date: 2011-03-24 16:09 |
| If you do: ./python -c "from concurrent.futures import *; from time import *; t = ProcessPoolExecutor(1); t.submit(sleep, 60)" and then kill the child process, the parent process doesn't notice and waits endlessly for the child to return the results. I'm using concurrent.futures here but I assume the bug (or limitation) is on the multiprocessing side? |
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| msg131998 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2011-03-24 16:16 |
| In the following example, if I kill the child process, the parent is immediatly done: --- from os import getpid from time import sleep from multiprocessing import Process def f(sec): print("child %s: wait %s seconds" % (getpid(), sec)) sleep(sec) if __name__ == '__main__': print("parent %s: wait child" % (getpid(),)) p = Process(target=f, args=(30,)) p.start() p.join() --- |
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| msg131999 - (view) |
Author: Antoine Pitrou (pitrou) * |
Date: 2011-03-24 16:18 |
| Le jeudi 24 mars 2011 à 16:16 +0000, STINNER Victor a écrit : > STINNER Victor <victor.stinner@haypocalc.com> added the comment: > > In the following example, if I kill the child process, the parent is immediatly done: > --- > from os import getpid > from time import sleep > from multiprocessing import Process concurrent.futures uses a multiprocessing.Queue to get the function results back. You should use a similar setup in your script. |
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| msg132004 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2011-03-24 16:33 |
| In the following example, the parent doesn't react when the child process is killed: ----- from os import getpid from time import sleep, time from multiprocessing import Pool def f(sec): print("child %s: wait %s seconds" % (getpid(), sec)) sleep(sec) if __name__ == '__main__': print("parent %s: wait child" % (getpid(),)) pool = Pool(processes=1) result = pool.apply_async(f, [60]) print(result.get(timeout=120)) print("parent: done") ----- |
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| msg132005 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2011-03-24 16:37 |
| It's possible to stop the parent with a CTRL+c, and so here is the trace of blocking function: $ ./python y.py parent 26706: wait child child 26707: wait 60 seconds ^CProcess PoolWorker-2: Traceback (most recent call last): File "y.py", line 13, in Traceback (most recent call last): File "/home/haypo/prog/HG/cpython/Lib/multiprocessing/process.py", line 263, in _bootstrap print(result.get(timeout=120)) File "/home/haypo/prog/HG/cpython/Lib/multiprocessing/pool.py", line 539, in get self.run() File "/home/haypo/prog/HG/cpython/Lib/multiprocessing/process.py", line 118, in run self._target(*self._args, **self._kwargs) File "/home/haypo/prog/HG/cpython/Lib/multiprocessing/pool.py", line 102, in worker self.wait(timeout) File "/home/haypo/prog/HG/cpython/Lib/multiprocessing/pool.py", line 534, in wait task = get() File "/home/haypo/prog/HG/cpython/Lib/multiprocessing/queues.py", line 378, in get return recv() KeyboardInterrupt self._cond.wait(timeout) File "/home/haypo/prog/HG/cpython/Lib/threading.py", line 241, in wait gotit = waiter.acquire(True, timeout) KeyboardInterrupt [61207 refs] |
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| msg132645 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2011-03-31 10:43 |
| This issue is a duplicate of #9205. |
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