| msg92971 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2009-09-22 02:28 |
| Worker processes with multiprocessing.Pool live for the duration of the Pool. If the tasks they run happen to leak memory (from a C extension module, or from creating cycles of unreachable objects, etc) or open files or other resources, there's no easy way to clean them up. Similarly, if one task passed to the pool allocates a large amount of memory, but further tasks are small, that additional memory isn't returned to the system because the process involved hasn't exited. A common approach to this problem (as used by Apache, mod_wsgi, and various other software) is to allow worker processes to exit (and be replaced with fresh processes) after completing a specified amount of work. The attached patch (against Python 2.6.2, but applies to various other versions with some fuzz) implements this as optional new behaviour in multiprocessing.Pool(). An additional optional argument is specified for the maximum number of tasks a worker process performs before it exits and is replaced with a fresh worker process. |
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| msg92987 - (view) |
Author: Jesse Noller (jnoller) *  |
Date: 2009-09-22 12:35 |
| Hi Charles; I don't see a doc update for this (see multiprocessing.rst) or unit tests. I'm not against it, but before I can commit this, I'll need those things |
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| msg92999 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2009-09-22 15:36 |
| Alright, I'll add those. Thanks for looking at it; first pass was mostly to ensure it wouldn't be wasted work. |
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| msg93191 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2009-09-28 04:03 |
| Updated patch attached; handles some of the Pool methods that weren't handled before. Now includes documentation and unit test additions as well. |
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| msg93517 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2009-10-04 00:42 |
| Jesse: this is ready for your review now. Thanks, Charles |
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| msg93916 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2009-10-13 03:22 |
| Can someone review this patch? I believe it's sufficient for inclusion now, as it includes docs and unit tests, but if anything about it requires further attention I'd be happy to listen to change requests. We'd like get this into mainline where everyone can benefit rather than continuing to maintain it out-of-tree. |
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| msg93920 - (view) |
Author: Jesse Noller (jnoller) * |
Date: 2009-10-13 13:43 |
| I plan on reviewing the patch once my work with PyCon is completed, which should be within the next few weeks. The next release this would show up in (2.7/3.2) is not for some time. |
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| msg93921 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2009-10-13 14:17 |
| Okay, thanks, Jesse. Didn't realize the Con was on. |
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| msg93923 - (view) |
Author: Jesse Noller (jnoller) * |
Date: 2009-10-13 14:24 |
| Well, it's in feb, but I'm involved in some intense planning right now. |
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| msg95243 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2009-11-14 16:43 |
| Hi Jesse -- Any chance you'll be able to review this in time for it to make it into trunk for the 2.7 alpha release? Charles |
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| msg95250 - (view) |
Author: Jesse Noller (jnoller) * |
Date: 2009-11-14 18:43 |
| On Sat, Nov 14, 2009 at 11:43 AM, Charles Cazabon <report@bugs.python.org> wrote: > > Charles Cazabon <charlesc-python@pyropus.ca> added the comment: > > Hi Jesse -- Any chance you'll be able to review this in time for it to > make it into trunk for the 2.7 alpha release? 2.7 isn't slated until next year some time, so yes. |
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| msg97832 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2010-01-15 18:46 |
| Ping... two alphas into 2.7. Have you had a chance to review this functionality? Thanks. |
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| msg97835 - (view) |
Author: Jesse Noller (jnoller) * |
Date: 2010-01-15 19:06 |
| I'm fine with the functionality; I'm going to test it out and look at committing it by mid-week next week. I apologize, I've been pretty maxed out. |
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| msg98032 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2010-01-18 20:48 |
| No problem, Jesse, I realize you're busy. I've updated the patch very slightly to handle an issue I had where the worker maintainer hung once. |
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| msg98129 - (view) |
Author: Jesse Noller (jnoller) * |
Date: 2010-01-22 02:49 |
| I'm working on this now; I'm going to need to port the patch to trunk before moving forward with it. Shouldn't take me long. |
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| msg98313 - (view) |
Author: Jesse Noller (jnoller) * |
Date: 2010-01-26 03:45 |
| Attached is the ported patch for Python 2.7/trunk. Please review it to make sure I didn't completely flub anything. I noticed you had forgotten the maxtasksperchild argument in the unit test, so I added that. I also expanded the docs a little but, paraphrasing your original post w.r.t to the justification. Let me know what you think, or if you have issues. Once you give the go ahead, I will commit to trunk and then merge to Py3k. Once again, thanks for the patch |
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| msg98382 - (view) |
Author: Charles Cazabon (charlesc) |
Date: 2010-01-26 21:27 |
| Thanks, Jesse -- it looks good. If there are bugs remaining in the patch, they're mine and not yours. |
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| msg98402 - (view) |
Author: Jesse Noller (jnoller) * |
Date: 2010-01-27 03:36 |
| Committed to trunk in r77794 Merged to Py3k in r77795 |
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