For comparison, here's the debug info on Win32 Python 2.71. Multiprocessing on Windows seems like a very different beast (e.g. there's no way to fork).
Case 1: In [1]: %cpaste Pasting code; enter '--' alone on the line to stop. :import multiprocessing as mp :import multiprocessing.util as util :util.log_to_stderr(util.SUBDEBUG) : :print(list(mp.Pool(1).imap(abs, range(3)))) :-- [DEBUG/MainProcess] created semlock with handle 604 [DEBUG/MainProcess] created semlock with handle 644 [DEBUG/MainProcess] added worker [DEBUG/MainProcess] doing set_length() [DEBUG/PoolWorker-1] recreated blocker with handle 36 [DEBUG/PoolWorker-1] recreated blocker with handle 48 [INFO/PoolWorker-1] child process calling self.run() [0, 1, 2] Case 2: In [1]: %cpaste Pasting code; enter '--' alone on the line to stop. :import multiprocessing as mp :import multiprocessing.util as util :util.log_to_stderr(util.SUBDEBUG) :pool=mp.Pool(1) :print list(pool.imap(abs, range(3))) :-- [DEBUG/MainProcess] created semlock with handle 604 [DEBUG/MainProcess] created semlock with handle 644 [DEBUG/MainProcess] added worker [DEBUG/MainProcess] doing set_length() [DEBUG/PoolWorker-1] recreated blocker with handle 24 [DEBUG/PoolWorker-1] recreated blocker with handle 32 [INFO/PoolWorker-1] child process calling self.run() [0, 1, 2] On Thursday, March 31, 2011 2:46:25 PM UTC-4, Yang Zhang wrote: > The problem was that Pool shuts down from its finalizer: > > http://stackoverflow.com/questions/5481104/multiprocessing-pool-imap-broken/5481610#5481610 > > On Wed, Mar 30, 2011 at 5:59 AM, eryksun () <ery...@gmail.com> wrote: > > On Tuesday, March 29, 2011 9:44:21 PM UTC-4, Yang Zhang wrote: > >> I've tried both the multiprocessing included in the python2.6 Ubuntu > >> package (__version__ says 0.70a1) and the latest from PyPI (2.6.2.1). > >> In both cases I don't know how to use imap correctly - it causes the > >> entire interpreter to stop responding to ctrl-C's. Any hints? Thanks > >> in advance. > >> > >> $ python > >> Python 2.6.5 (r265:79063, Apr 16 2010, 13:57:41) > >> [GCC 4.4.3] on linux2 > >> Type "help", "copyright", "credits" or "license" for more information. > >> >>> import multiprocessing as mp > >> >>> mp.Pool(1).map(abs, range(3)) > >> [0, 1, 2] > >> >>> list(mp.Pool(1).imap(abs, range(3))) > >> ^C^C^C^C^\Quit > > > > It works fine for me on Win32 Python 2.7.1 with multiprocessing 0.70a1. So > > it's probably an issue with the implementation on Linux. > > > > Python 2.7.1 (r271:86832, Nov 27 2010, 18:30:46) > > [MSC v.1500 32 bit (Intel)] on win32 > > Type "help", "copyright", "credits" or "license" for more information. > >>>> import multiprocessing as mp > >>>> list(mp.Pool(1).imap(abs, range(3))) > > [0, 1, 2] > >>>> mp.__version__ > > '0.70a1' > > -- > > http://mail.python.org/mailman/listinfo/python-list > > > > > > -- > Yang Zhang > http://yz.mit.edu/ -- http://mail.python.org/mailman/listinfo/python-list
