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Created on 2012-08-27 22:35 by skrah, last changed 2022-04-11 14:57 by admin. This issue is now closed.
| Files | ||||
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| File name | Uploaded | Description | Edit | |
| relax_deadlock_test.patch | pitrou, 2012-08-28 00:05 | review | ||
| Messages (5) | |||
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| msg169232 - (view) | Author: Stefan Krah (skrah) *  |
Date: 2012-08-27 22:35 | |
On the obstinate i7 machine (see #15781), test_importlib fails sporadically (after 10 repetitions or so). $ ./python -m test -uall -F test_importlib [ 1] test_importlib test test_importlib failed -- Traceback (most recent call last): File "/home/stefan/hg/cpython/Lib/test/test_importlib/test_locks.py", line 80, in test_deadlock self.assertEqual(results.count((True, False)), 1) AssertionError: 2 != 1 1 test failed: test_importlib |
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| msg169238 - (view) | Author: Stefan Krah (skrah) * |
Date: 2012-08-27 22:47 | |
Also reproduced on Ubuntu Lucid/Core 2 Duo with a very low switch interval and -j4. It takes more repetitions than on the i7: $ ./python -m test -uall -F -j4 test_importlib [...] [224] test_importlib [225] test_importlib [226/1] test_importlib test test_importlib failed -- Traceback (most recent call last): File "/home/stefan/pydev/cpython/Lib/test/test_importlib/test_locks.py", line 80, in test_deadlock self.assertEqual(results.count((True, False)), 1) AssertionError: 2 != 1 |
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| msg169239 - (view) | Author: Antoine Pitrou (pitrou) * |
Date: 2012-08-28 00:05 | |
After a bit of investigation, it turns out the test is probably too strict. The deadlock avoidance logic in importlib._bootstrap is indeed conservative: if you take a look at _ModuleLock.acquire(), _blocking_on[tid] is set even while other threads may run, because the internal lock is not always taken. Therefore, if there's a potential deadlock between several threads, there are situations where DeadlockError will be raised in two threads, not only one. (IMHO it would complicate the code too much to make deadlock avoidance less conservative, without bringing anything in terms of additional functionality) See attached patch. |
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| msg169257 - (view) | Author: Stefan Krah (skrah) * |
Date: 2012-08-28 09:00 | |
The patch works fine here (as expected). |
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| msg169290 - (view) | Author: Roundup Robot (python-dev)  |
Date: 2012-08-28 18:13 | |
New changeset 454dceb5fd56 by Antoine Pitrou in branch 'default': Issue #15794: Relax a test case due to the deadlock detection's conservativeness. http://hg.python.org/cpython/rev/454dceb5fd56 |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:57:35 | admin | set | github: 59998 |
| 2012-08-28 18:14:47 | pitrou | set | status: open -> closed resolution: fixed stage: resolved |
| 2012-08-28 18:13:55 | python-dev | set | nosy:
+ python-dev messages: + msg169290 |
| 2012-08-28 09:00:49 | skrah | set | messages: + msg169257 |
| 2012-08-28 00:05:20 | pitrou | set | files:
+ relax_deadlock_test.patch keywords: + patch messages: + msg169239 |
| 2012-08-27 22:47:18 | skrah | set | messages: + msg169238 |
| 2012-08-27 22:35:01 | skrah | create | |