gh-139103: Improve namedtuple scaling in free-threaded build #144332
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Add `_Py_type_getattro_stackref`, a variant of type attribute lookup that returns `_PyStackRef` instead of `PyObject*`. This allows returning deferred references in the free-threaded build, reducing reference count contention when accessing type attributes. This significantly improves scaling of namedtuple instantiation across multiple threads.
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FYI, I think I'm going to try splitting out parts of this into other PRs. |
Thanks, since this PR is quite big :-) |
Objects/funcobject.c
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| staticmethod *sm = (staticmethod *) | ||
| PyType_GenericAlloc(&PyStaticMethod_Type, 0); | ||
| if (sm != NULL) { | ||
| _PyObject_SetDeferredRefcount((PyObject *)sm); |
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Should we also call it in sm_init()? If not, should we move this _PyObject_SetDeferredRefcount() call to typeobject.c after the two PyStaticMethod_New() calls?
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Hmmm... maybe? We'll need to guard the call to _PyObject_SetDeferredRefcount() because calling it multiple times on the same object will trigger an assertion failure.
I'll update this after your PR is merged
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I merged for classmethod/staticmethod fix in the main branch.
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I've put the calls to _PyObject_SetDeferredRefcount() in sm_new() and PyStaticMethod_New() so that it's called exactly once during construction.
Co-authored-by: Victor Stinner <vstinner@python.org>
Co-authored-by: Victor Stinner <vstinner@python.org>
Co-authored-by: Victor Stinner <vstinner@python.org>
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_Py_type_getattro_stackref, a variant of type attribute lookup that returns_PyStackRefinstead ofPyObject*. This allows returning deferred references in the free-threaded build, reducing reference count contention when accessing type attributes.This improves scaling of namedtuple instantiation across multiple threads.