Description

encukou

opened on Jan 30, 2024

Issue body actions

test.test_capi.test_misc.TestPendingCalls.test_pendingcalls_threaded usually (but not always) times out on the AMD64 Windows Server 2022 NoGIL 3.x buildbot, e.g. here: https://buildbot.python.org/all/#/builders/1241/builds/1116/steps/4/logs/stdio

It started 5 days ago, after #114262 (Implement GC for free-threaded builds) and #114479 (Make threading.Lock a real class, not a factory function), and it looks like it got more frequent after #113412 (Use pointer for interp->obmalloc state). (This is just from looking at the buildbot logs, I haven't bisected.)

Linked PRs

• gh-114746: Avoid quadratic behavior in free-threaded GC #114817

Activity

1. encukou

   added

   topic-free-threading

   on Jan 30, 2024
2. encukou commented on Jan 30, 2024

   

   encukou

   on Jan 30, 2024

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   I cannot reproduce on my Windows 11 (10.0.22621.3007) VM :(

   Faulthandler tracebacks (with source lines added):

   Thread 0x00001f80 (most recent call first):
     File "C:\Users\Administrator\buildarea\3.x.itamaro-win64-srv-22-aws.x64.nogil\build\Lib\test\test_capi\test_misc.py", line 1344 in pendingcalls_thread
       context.event.set()
     File "C:\Users\Administrator\buildarea\3.x.itamaro-win64-srv-22-aws.x64.nogil\build\Lib\threading.py", line 1027 in run
   ...
   
   Thread 0x000032d0 (most recent call first):
     File "C:\Users\Administrator\buildarea\3.x.itamaro-win64-srv-22-aws.x64.nogil\build\Lib\test\test_capi\test_misc.py", line 1304 in pendingcalls_wait
       a = i*i
     File "C:\Users\Administrator\buildarea\3.x.itamaro-win64-srv-22-aws.x64.nogil\build\Lib\test\test_capi\test_misc.py", line 1332 in test_pendingcalls_threaded
       self.pendingcalls_wait(context.l, n, context)
   ...
   
3. AlexWaygood

   added

   OS-windows

   on Jan 30, 2024
4. terryjreedy commented on Jan 31, 2024

   

   terryjreedy

   on Jan 31, 2024

   Member

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   On my Win10 fresh debug nogil build, test.test_capi paused several minutes on
   test_trashcan_python_class1 (test.test_capi.test_misc.CAPITest.test_trashcan_python_class1)
   I went away to eat and upon return it had finished ok in 14 minutes, which I believe is a few times as long as normal.
5. encukou commented on Jan 31, 2024

   

   encukou

   on Jan 31, 2024

   MemberAuthor

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   @colesbury Is this a high-priority issue for you, or normal behaviour at this stage of the feature?
   We might want to increase the timeout, and revisit GC performance later.
6. colesbury commented on Jan 31, 2024

   

   colesbury

   on Jan 31, 2024

   Contributor

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   @encukou I'm planning to put out a PR to fix it today

   Reacted by Petr Viktorin
7. colesbury

   self-assigned this

   on Jan 31, 2024
8. colesbury

   added a commit that references this issue on Jan 31, 2024

   pythongh-114746: Avoid quadratic behavior in free-threaded GC

   66959ca
9. encukou

   added a commit that references this issue on Feb 1, 2024

   gh-114746: Avoid quadratic behavior in free-threaded GC (GH-114817)

   e6d6d5d
10. colesbury commented on Feb 1, 2024

    

    colesbury

    on Feb 1, 2024

    Contributor

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    The six builds since the PR merged are all green: https://buildbot.python.org/all/#/builders/1241
11. colesbury

    closed this as completedon Feb 1, 2024
12. aisk

    added a commit that references this issue on Feb 11, 2024

    pythongh-114746: Avoid quadratic behavior in free-threaded GC (python…

    d2c693e

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