On Fri, 2010-10-29 at 08:12 -0400, Neal Becker wrote: > Seems multiprocessing doesn't behave well with signals: > --------- > from multiprocessing import Pool > import time > def sleep (dummy): > time.sleep (10) > if __name__ == '__main__': > pool = Pool (processes=2) > result = pool.map (sleep, range (4)) > ------------- > start it up > $ python test_multip.py > ---------------------- > ps auxf | grep python > nbecker 6605 1.6 0.1 338192 6952 pts/1 Sl+ 08:03 0:00 | \_ > python test_multip.py > nbecker 6606 0.0 0.1 186368 4760 pts/1 S+ 08:03 0:00 | > \_ python test_multip.py > nbecker 6607 0.0 0.1 186372 4740 pts/1 S+ 08:03 0:00 | > \_ python test_multip.py > kill 6607 > ps auxf | grep python > nbecker 6605 0.5 0.1 338192 6952 pts/1 Sl+ 08:03 0:00 | \_ > python test_multip.py > nbecker 6606 0.0 0.1 186368 4760 pts/1 S+ 08:03 0:00 | > \_ python test_multip.py > nbecker 6607 0.0 0.0 0 0 pts/1 Z+ 08:03 0:00 | > \_ [python] <defunct> > kill 6606 > ps auxf | grep python > nbecker 6605 0.3 0.1 338192 6952 pts/1 Sl+ 08:03 0:00 | \_ > python test_multip.py > nbecker 6606 0.0 0.0 0 0 pts/1 Z+ 08:03 0:00 | > \_ [python] <defunct> > nbecker 6607 0.0 0.0 0 0 pts/1 Z+ 08:03 0:00 | > \_ [python] <defunct> > Now we have 2 dead children and the parent is hung forever. > Isn't this a serious defect?
No, I think this is just POSIX/UNIX process behavior. If the parent never joins on the child the child can never exit [which is what a Zombie process is]. For example, see the do_verify_workers method in <http://coils.hg.sourceforge.net/hgweb/coils/coils/file/6ab5ade3e488/src/coils/logic/workflow/services/executor.py> A parent process needs to make some effort to reap its children. -- http://mail.python.org/mailman/listinfo/python-list
