My test reduction:
import multiprocessing
import queue
def _process_worker(q):
while True:
try:
something = q.get(block=True, timeout=0.1)
except queue.Empty:
return
else:
print('Grabbed item from queue:', something)
def _make_some_processes(q):
processes = []
for _ in range(10):
p = multiprocessing.Process(target=_process_worker, args=(q,))
p.start()
processes.append(p)
return processes
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
# The deadlock only occurs on Mac OS X and only when these lines
# are commented out:
# for p in processes:
# p.join()
for i in range(100):
_do(i)
--------------
Output (on Mac OS X using the svn version of py3k):
% ~/bin/python3.2 moprocessmoproblems.py
Run: 0
Grabbed item from queue: 0
Grabbed item from queue: 1
Grabbed item from queue: 2
...
Grabbed item from queue: 29
Run: 1
At this point the script produces no additional output. If I uncomment
the lines above then the script produces the expected output. I don't
see any docs that would explain this problem and I don't know what the
rule would be e.g. you just join every process that uses a queue before
the queue is garbage collected.
Any ideas why this is happening?
Cheers,
Brian
--
http://mail.python.org/mailman/listinfo/python-list
