diff --git a/Include/internal/pycore_freelist_state.h b/Include/internal/pycore_freelist_state.h index 2ccd1ac055b747..7c252f5b570c13 100644 --- a/Include/internal/pycore_freelist_state.h +++ b/Include/internal/pycore_freelist_state.h @@ -11,6 +11,8 @@ extern "C" { # define PyTuple_MAXSAVESIZE 20 // Largest tuple to save on freelist # define Py_tuple_MAXFREELIST 2000 // Maximum number of tuples of each size to save # define Py_lists_MAXFREELIST 80 +# define Py_list_iters_MAXFREELIST 10 +# define Py_tuple_iters_MAXFREELIST 10 # define Py_dicts_MAXFREELIST 80 # define Py_dictkeys_MAXFREELIST 80 # define Py_floats_MAXFREELIST 100 @@ -40,6 +42,8 @@ struct _Py_freelists { struct _Py_freelist ints; struct _Py_freelist tuples[PyTuple_MAXSAVESIZE]; struct _Py_freelist lists; + struct _Py_freelist list_iters; + struct _Py_freelist tuple_iters; struct _Py_freelist dicts; struct _Py_freelist dictkeys; struct _Py_freelist slices; diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2025-01-07-19-26-40.gh-issue-126703.9i-S5t.rst b/Misc/NEWS.d/next/Core_and_Builtins/2025-01-07-19-26-40.gh-issue-126703.9i-S5t.rst new file mode 100644 index 00000000000000..dcd5f449c98ef3 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2025-01-07-19-26-40.gh-issue-126703.9i-S5t.rst @@ -0,0 +1 @@ +Improve performance of iterating over lists and tuples by using a freelist for the iterator objects. diff --git a/Objects/listobject.c b/Objects/listobject.c index 099e65c0c25fed..f4a269e4d7b284 100644 --- a/Objects/listobject.c +++ b/Objects/listobject.c @@ -3903,15 +3903,17 @@ PyTypeObject PyListIter_Type = { static PyObject * list_iter(PyObject *seq) { - _PyListIterObject *it; - if (!PyList_Check(seq)) { PyErr_BadInternalCall(); return NULL; } - it = PyObject_GC_New(_PyListIterObject, &PyListIter_Type); - if (it == NULL) - return NULL; + _PyListIterObject *it = _Py_FREELIST_POP(_PyListIterObject, list_iters); + if (it == NULL) { + it = PyObject_GC_New(_PyListIterObject, &PyListIter_Type); + if (it == NULL) { + return NULL; + } + } it->it_index = 0; it->it_seq = (PyListObject *)Py_NewRef(seq); _PyObject_GC_TRACK(it); @@ -3924,7 +3926,8 @@ listiter_dealloc(PyObject *self) _PyListIterObject *it = (_PyListIterObject *)self; _PyObject_GC_UNTRACK(it); Py_XDECREF(it->it_seq); - PyObject_GC_Del(it); + assert(Py_IS_TYPE(self, &PyListIter_Type)); + _Py_FREELIST_FREE(list_iters, it, PyObject_GC_Del); } static int diff --git a/Objects/object.c b/Objects/object.c index 51b6016b9c191c..6ca13a3b431659 100644 --- a/Objects/object.c +++ b/Objects/object.c @@ -923,6 +923,8 @@ _PyObject_ClearFreeLists(struct _Py_freelists *freelists, int is_finalization) clear_freelist(&freelists->tuples[i], is_finalization, free_object); } clear_freelist(&freelists->lists, is_finalization, free_object); + clear_freelist(&freelists->list_iters, is_finalization, free_object); + clear_freelist(&freelists->tuple_iters, is_finalization, free_object); clear_freelist(&freelists->dicts, is_finalization, free_object); clear_freelist(&freelists->dictkeys, is_finalization, PyMem_Free); clear_freelist(&freelists->slices, is_finalization, free_object); diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c index 7fe8553030a02e..60af9e40e3fe83 100644 --- a/Objects/tupleobject.c +++ b/Objects/tupleobject.c @@ -993,7 +993,8 @@ tupleiter_dealloc(PyObject *self) _PyTupleIterObject *it = _PyTupleIterObject_CAST(self); _PyObject_GC_UNTRACK(it); Py_XDECREF(it->it_seq); - PyObject_GC_Del(it); + assert(Py_IS_TYPE(self, &PyTupleIter_Type)); + _Py_FREELIST_FREE(tuple_iters, it, PyObject_GC_Del); } static int @@ -1119,15 +1120,16 @@ PyTypeObject PyTupleIter_Type = { static PyObject * tuple_iter(PyObject *seq) { - _PyTupleIterObject *it; - if (!PyTuple_Check(seq)) { PyErr_BadInternalCall(); return NULL; } - it = PyObject_GC_New(_PyTupleIterObject, &PyTupleIter_Type); - if (it == NULL) - return NULL; + _PyTupleIterObject *it = _Py_FREELIST_POP(_PyTupleIterObject, tuple_iters); + if (it == NULL) { + it = PyObject_GC_New(_PyTupleIterObject, &PyTupleIter_Type); + if (it == NULL) + return NULL; + } it->it_index = 0; it->it_seq = (PyTupleObject *)Py_NewRef(seq); _PyObject_GC_TRACK(it);