https://github.com/python/cpython/commit/166c56b31162924ddbb594b67169004882dd1c07 commit: 166c56b31162924ddbb594b67169004882dd1c07 branch: 3.15 author: Miss Islington (bot) <[email protected]> committer: kumaraditya303 <[email protected]> date: 2026-05-13T18:09:33Z summary:
[3.15] gh-148906: fix performance scaling of descriptors on free-threading (GH-148915) (#149798) gh-148906: fix performance scaling of descriptors on free-threading (GH-148915) (cherry picked from commit 94bca40ff09c20f6168d6a27e3aa42bf8a8077b8) Co-authored-by: Kumar Aditya <[email protected]> files: M Objects/typeobject.c M Tools/ftscalingbench/ftscalingbench.py diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 9a18ca72516da7..7cca137f74be58 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -4841,6 +4841,18 @@ type_new_set_attrs(const type_new_ctx *ctx, PyTypeObject *type) if (type_new_set_classdictcell(dict) < 0) { return -1; } + +#ifdef Py_GIL_DISABLED + // enable deferred reference counting on functions and descriptors + Py_ssize_t pos = 0; + PyObject *key, *value; + while (PyDict_Next(dict, &pos, &key, &value)) { + if (PyFunction_Check(value) || Py_TYPE(value)->tp_descr_get != NULL) { + PyUnstable_Object_EnableDeferredRefcount(value); + } + } +#endif + return 0; } @@ -6746,12 +6758,11 @@ type_setattro(PyObject *self, PyObject *name, PyObject *value) assert(!_PyType_HasFeature(metatype, Py_TPFLAGS_MANAGED_DICT)); #ifdef Py_GIL_DISABLED - // gh-139103: Enable deferred refcounting for functions assigned - // to type objects. This is important for `dataclass.__init__`, - // which is generated dynamically. - if (value != NULL && - PyFunction_Check(value) && - !_PyObject_HasDeferredRefcount(value)) + // gh-139103: Enable deferred refcounting for functions and descriptors + // assigned to type objects. This is important for `dataclass.__init__`, + // which is generated dynamically, and for descriptor scaling on + // free-threaded builds. + if (value != NULL && (PyFunction_Check(value) || Py_TYPE(value)->tp_descr_get != NULL)) { PyUnstable_Object_EnableDeferredRefcount(value); } @@ -11089,10 +11100,12 @@ static PyObject * slot_tp_descr_get(PyObject *self, PyObject *obj, PyObject *type) { PyTypeObject *tp = Py_TYPE(self); - PyObject *get; - - get = _PyType_LookupRef(tp, &_Py_ID(__get__)); - if (get == NULL) { + PyThreadState *tstate = _PyThreadState_GET(); + _PyCStackRef cref; + _PyThreadState_PushCStackRef(tstate, &cref); + _PyType_LookupStackRefAndVersion(tp, &_Py_ID(__get__), &cref.ref); + if (PyStackRef_IsNull(cref.ref)) { + _PyThreadState_PopCStackRef(tstate, &cref); #ifndef Py_GIL_DISABLED /* Avoid further slowdowns */ if (tp->tp_descr_get == slot_tp_descr_get) @@ -11104,9 +11117,10 @@ slot_tp_descr_get(PyObject *self, PyObject *obj, PyObject *type) obj = Py_None; if (type == NULL) type = Py_None; + PyObject *get = PyStackRef_AsPyObjectBorrow(cref.ref); PyObject *stack[3] = {self, obj, type}; PyObject *res = PyObject_Vectorcall(get, stack, 3, NULL); - Py_DECREF(get); + _PyThreadState_PopCStackRef(tstate, &cref); return res; } diff --git a/Tools/ftscalingbench/ftscalingbench.py b/Tools/ftscalingbench/ftscalingbench.py index 60f43b99c0f69d..c8a914c22a9e13 100644 --- a/Tools/ftscalingbench/ftscalingbench.py +++ b/Tools/ftscalingbench/ftscalingbench.py @@ -279,6 +279,23 @@ def staticmethod_call(): for _ in range(1000 * WORK_SCALE): obj.my_staticmethod() + +class MyDescriptor: + def __get__(self, obj, objtype=None): + return 42 + + def __set__(self, obj, value): + pass + +class MyClassWithDescriptor: + attr = MyDescriptor() + +@register_benchmark +def descriptor(): + obj = MyClassWithDescriptor() + for _ in range(1000 * WORK_SCALE): + obj.attr + @register_benchmark def deepcopy(): x = {'list': [1, 2], 'tuple': (1, None)} _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
