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Optimize slots: avoid temporary PyMethodObject 

Issue #29507: Optimize slots calling Python methods. For Python methods, get
the unbound Python function and prepend arguments with self, rather than
calling the descriptor which creates a temporary PyMethodObject.

Add a new _PyObject_FastCall_Prepend() function used to call the unbound Python
method with self. It avoids the creation of a temporary tuple to pass
positional arguments.

Avoiding temporary PyMethodObject and avoiding temporary tuple makes Python
slots up to 1.46x faster. Microbenchmark on a __getitem__() method implemented
in Python:

Median +- std dev: 121 ns +- 5 ns -> 82.8 ns +- 1.0 ns: 1.46x faster (-31%)

Co-Authored-by: INADA Naoki <songofacandy@gmail.com>
This commit is contained in:
Victor Stinner 2017-02-09 22:53:47 +01:00
parent c42c65574d
commit 516b98161a
3 changed files with 166 additions and 58 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
Include/abstract.h
View File

@ -257,6 +257,12 @@ PyAPI_FUNC(PyObject *) _PyObject_Call_Prepend(
PyObject *args,
PyObject *kwargs);
PyAPI_FUNC(PyObject *) _PyObject_FastCall_Prepend(
PyObject *callable,
PyObject *obj,
PyObject **args,
Py_ssize_t nargs);
PyAPI_FUNC(PyObject *) _Py_CheckFunctionResult(PyObject *callable,
PyObject *result,
const char *where);

35
Objects/abstract.c
View File

@ -2367,6 +2367,41 @@ _PyObject_FastCallDict(PyObject *callable, PyObject **args, Py_ssize_t nargs,
/* Positional arguments are obj followed by args:
call callable(obj, *args, **kwargs) */
PyObject *
_PyObject_FastCall_Prepend(PyObject *callable,
PyObject *obj, PyObject **args, Py_ssize_t nargs)
{
PyObject *small_stack[_PY_FASTCALL_SMALL_STACK];
PyObject **args2;
PyObject *result;
nargs++;
if (nargs <= (Py_ssize_t)Py_ARRAY_LENGTH(small_stack)) {
args2 = small_stack;
}
else {
args2 = PyMem_Malloc(nargs * sizeof(PyObject *));
if (args2 == NULL) {
PyErr_NoMemory();
return NULL;
}
}
/* use borrowed references */
args2[0] = obj;
memcpy(&args2[1],
args,
(nargs - 1)* sizeof(PyObject *));
result = _PyObject_FastCall(callable, args2, nargs);
if (args2 != small_stack) {
PyMem_Free(args2);
}
return result;
}
/* Call callable(obj, *args, **kwargs). */
PyObject *
_PyObject_Call_Prepend(PyObject *callable,
PyObject *obj, PyObject *args, PyObject *kwargs)
{

179
Objects/typeobject.c
View File

@ -1394,14 +1394,18 @@ PyType_IsSubtype(PyTypeObject *a, PyTypeObject *b)
the method name as a C string, and the address of a
static variable used to cache the interned Python string.
Two variants:
Variants:
- lookup_maybe() returns NULL without raising an exception
when the _PyType_Lookup() call fails;
- lookup_method() always raises an exception upon errors.
- lookup_maybe_method() and lookup_method() are similar to
lookup_maybe(), but can return unbound PyFunction
to avoid temporary method object. Pass self as first argument when
unbound == 1.
- _PyObject_LookupSpecial() exported for the benefit of other places.
- _PyObject_LookupSpecial() expose lookup_maybe for the benefit of
other places.
*/
static PyObject *
@ -1421,11 +1425,38 @@ lookup_maybe(PyObject *self, _Py_Identifier *attrid)
}
static PyObject *
lookup_method(PyObject *self, _Py_Identifier *attrid)
lookup_maybe_method(PyObject *self, _Py_Identifier *attrid, int *unbound)
{
PyObject *res = lookup_maybe(self, attrid);
if (res == NULL && !PyErr_Occurred())
PyObject *res = _PyType_LookupId(Py_TYPE(self), attrid);
if (res == NULL) {
return NULL;
}
if (PyFunction_Check(res)) {
/* Avoid temporary PyMethodObject */
*unbound = 1;
Py_INCREF(res);
}
else {
*unbound = 0;
descrgetfunc f = Py_TYPE(res)->tp_descr_get;
if (f == NULL) {
Py_INCREF(res);
}
else {
res = f(res, self, (PyObject *)(Py_TYPE(self)));
}
}
return res;
}
static PyObject *
lookup_method(PyObject *self, _Py_Identifier *attrid, int *unbound)
{
PyObject *res = lookup_maybe_method(self, attrid, unbound);
if (res == NULL && !PyErr_Occurred()) {
PyErr_SetObject(PyExc_AttributeError, attrid->object);
}
return res;
}
@ -1435,26 +1466,49 @@ _PyObject_LookupSpecial(PyObject *self, _Py_Identifier *attrid)
return lookup_maybe(self, attrid);
}
/* A variation of PyObject_CallMethodObjArgs that uses lookup_method()
instead of PyObject_GetAttrString(). This uses the same convention
as lookup_method to cache the interned name string object. */
static PyObject*
call_unbound(int unbound, PyObject *func, PyObject *self,
PyObject **args, Py_ssize_t nargs)
{
if (unbound) {
return _PyObject_FastCall_Prepend(func, self, args, nargs);
}
else {
return _PyObject_FastCall(func, args, nargs);
}
}
static PyObject*
call_unbound_noarg(int unbound, PyObject *func, PyObject *self)
{
if (unbound) {
PyObject *args[1] = {self};
return _PyObject_FastCall(func, args, 1);
}
else {
return _PyObject_CallNoArg(func);
}
}
/* A variation of PyObject_CallMethodObjArgs that uses lookup_maybe_method()
instead of PyObject_GetAttrString(). This uses the same convention
as lookup_maybe_method to cache the interned name string object. */
static PyObject *
call_method(PyObject *obj, _Py_Identifier *name,
PyObject **args, Py_ssize_t nargs)
{
int unbound;
PyObject *func, *retval;
func = lookup_maybe(obj, name);
func = lookup_maybe_method(obj, name, &unbound);
if (func == NULL) {
if (!PyErr_Occurred())
PyErr_SetObject(PyExc_AttributeError, name->object);
return NULL;
}
retval = _PyObject_FastCall(func, args, nargs);
retval = call_unbound(unbound, func, obj, args, nargs);
Py_DECREF(func);
return retval;
}
@ -1464,18 +1518,18 @@ static PyObject *
call_maybe(PyObject *obj, _Py_Identifier *name,
PyObject **args, Py_ssize_t nargs)
{
int unbound;
PyObject *func, *retval;
func = lookup_maybe(obj, name);
func = lookup_maybe_method(obj, name, &unbound);
if (func == NULL) {
if (!PyErr_Occurred())
Py_RETURN_NOTIMPLEMENTED;
return NULL;
}
retval = _PyObject_FastCall(func, args, nargs);
retval = call_unbound(unbound, func, obj, args, nargs);
Py_DECREF(func);
return retval;
}
@ -1830,10 +1884,12 @@ mro_invoke(PyTypeObject *type)
if (custom) {
_Py_IDENTIFIER(mro);
PyObject *mro_meth = lookup_method((PyObject *)type, &PyId_mro);
int unbound;
PyObject *mro_meth = lookup_method((PyObject *)type, &PyId_mro,
&unbound);
if (mro_meth == NULL)
return NULL;
mro_result = _PyObject_CallNoArg(mro_meth);
mro_result = call_unbound_noarg(unbound, mro_meth, (PyObject *)type);
Py_DECREF(mro_meth);
}
else {
@ -5892,10 +5948,10 @@ static int
slot_sq_contains(PyObject *self, PyObject *value)
{
PyObject *func, *res;
int result = -1;
int result = -1, unbound;
_Py_IDENTIFIER(__contains__);
func = lookup_maybe(self, &PyId___contains__);
func = lookup_maybe_method(self, &PyId___contains__, &unbound);
if (func == Py_None) {
Py_DECREF(func);
PyErr_Format(PyExc_TypeError,
@ -5904,7 +5960,8 @@ slot_sq_contains(PyObject *self, PyObject *value)
return -1;
}
if (func != NULL) {
res = PyObject_CallFunctionObjArgs(func, value, NULL);
PyObject *args[1] = {value};
res = call_unbound(unbound, func, self, args, 1);
Py_DECREF(func);
if (res != NULL) {
result = PyObject_IsTrue(res);
@ -5982,17 +6039,17 @@ static int
slot_nb_bool(PyObject *self)
{
PyObject *func, *value;
int result;
int result, unbound;
int using_len = 0;
_Py_IDENTIFIER(__bool__);
func = lookup_maybe(self, &PyId___bool__);
func = lookup_maybe_method(self, &PyId___bool__, &unbound);
if (func == NULL) {
if (PyErr_Occurred()) {
return -1;
}
func = lookup_maybe(self, &PyId___len__);
func = lookup_maybe_method(self, &PyId___len__, &unbound);
if (func == NULL) {
if (PyErr_Occurred()) {
return -1;
@ -6002,7 +6059,7 @@ slot_nb_bool(PyObject *self)
using_len = 1;
}
value = _PyObject_CallNoArg(func);
value = call_unbound_noarg(unbound, func, self);
if (value == NULL) {
goto error;
}
@ -6078,10 +6135,11 @@ slot_tp_repr(PyObject *self)
{
PyObject *func, *res;
_Py_IDENTIFIER(__repr__);
int unbound;
func = lookup_method(self, &PyId___repr__);
func = lookup_method(self, &PyId___repr__, &unbound);
if (func != NULL) {
res = PyEval_CallObject(func, NULL);
res = call_unbound_noarg(unbound, func, self);
Py_DECREF(func);
return res;
}
@ -6090,27 +6148,16 @@ slot_tp_repr(PyObject *self)
Py_TYPE(self)->tp_name, self);
}
static PyObject *
slot_tp_str(PyObject *self)
{
PyObject *func, *res;
_Py_IDENTIFIER(__str__);
func = lookup_method(self, &PyId___str__);
if (func == NULL)
return NULL;
res = PyEval_CallObject(func, NULL);
Py_DECREF(func);
return res;
}
SLOT0(slot_tp_str, "__str__")
static Py_hash_t
slot_tp_hash(PyObject *self)
{
PyObject *func, *res;
Py_ssize_t h;
int unbound;
func = lookup_method(self, &PyId___hash__);
func = lookup_method(self, &PyId___hash__, &unbound);
if (func == Py_None) {
Py_DECREF(func);
@ -6121,7 +6168,7 @@ slot_tp_hash(PyObject *self)
return PyObject_HashNotImplemented(self);
}
res = PyEval_CallObject(func, NULL);
res = call_unbound_noarg(unbound, func, self);
Py_DECREF(func);
if (res == NULL)
return -1;
@ -6155,13 +6202,19 @@ static PyObject *
slot_tp_call(PyObject *self, PyObject *args, PyObject *kwds)
{
_Py_IDENTIFIER(__call__);
PyObject *meth = lookup_method(self, &PyId___call__);
int unbound;
PyObject *meth = lookup_method(self, &PyId___call__, &unbound);
PyObject *res;
if (meth == NULL)
return NULL;
if (unbound) {
res = _PyObject_Call_Prepend(meth, self, args, kwds);
}
else {
res = PyObject_Call(meth, args, kwds);
}
Py_DECREF(meth);
return res;
@ -6280,14 +6333,17 @@ static _Py_Identifier name_op[] = {
static PyObject *
slot_tp_richcompare(PyObject *self, PyObject *other, int op)
{
int unbound;
PyObject *func, *res;
func = lookup_method(self, &name_op[op]);
func = lookup_method(self, &name_op[op], &unbound);
if (func == NULL) {
PyErr_Clear();
Py_RETURN_NOTIMPLEMENTED;
}
res = PyObject_CallFunctionObjArgs(func, other, NULL);
PyObject *args[1] = {other};
res = call_unbound(unbound, func, self, args, 1);
Py_DECREF(func);
return res;
}
@ -6295,10 +6351,11 @@ slot_tp_richcompare(PyObject *self, PyObject *other, int op)
static PyObject *
slot_tp_iter(PyObject *self)
{
int unbound;
PyObject *func, *res;
_Py_IDENTIFIER(__iter__);
func = lookup_method(self, &PyId___iter__);
func = lookup_method(self, &PyId___iter__, &unbound);
if (func == Py_None) {
Py_DECREF(func);
PyErr_Format(PyExc_TypeError,
@ -6308,13 +6365,13 @@ slot_tp_iter(PyObject *self)
}
if (func != NULL) {
res = _PyObject_CallNoArg(func);
res = call_unbound_noarg(unbound, func, self);
Py_DECREF(func);
return res;
}
PyErr_Clear();
func = lookup_method(self, &PyId___getitem__);
func = lookup_method(self, &PyId___getitem__, &unbound);
if (func == NULL) {
PyErr_Format(PyExc_TypeError,
"'%.200s' object is not iterable",
@ -6380,12 +6437,18 @@ static int
slot_tp_init(PyObject *self, PyObject *args, PyObject *kwds)
{
_Py_IDENTIFIER(__init__);
PyObject *meth = lookup_method(self, &PyId___init__);
int unbound;
PyObject *meth = lookup_method(self, &PyId___init__, &unbound);
PyObject *res;
if (meth == NULL)
return -1;
if (unbound) {
res = _PyObject_Call_Prepend(meth, self, args, kwds);
}
else {
res = PyObject_Call(meth, args, kwds);
}
Py_DECREF(meth);
if (res == NULL)
return -1;
@ -6419,6 +6482,7 @@ static void
slot_tp_finalize(PyObject *self)
{
_Py_IDENTIFIER(__del__);
int unbound;
PyObject *del, *res;
PyObject *error_type, *error_value, *error_traceback;
@ -6426,9 +6490,9 @@ slot_tp_finalize(PyObject *self)
PyErr_Fetch(&error_type, &error_value, &error_traceback);
/* Execute __del__ method, if any. */
del = lookup_maybe(self, &PyId___del__);
del = lookup_maybe_method(self, &PyId___del__, &unbound);
if (del != NULL) {
res = PyEval_CallObject(del, NULL);
res = call_unbound_noarg(unbound, del, self);
if (res == NULL)
PyErr_WriteUnraisable(del);
else
@ -6443,12 +6507,13 @@ slot_tp_finalize(PyObject *self)
static PyObject *
slot_am_await(PyObject *self)
{
int unbound;
PyObject *func, *res;
_Py_IDENTIFIER(__await__);
func = lookup_method(self, &PyId___await__);
func = lookup_method(self, &PyId___await__, &unbound);
if (func != NULL) {
res = PyEval_CallObject(func, NULL);
res = call_unbound_noarg(unbound, func, self);
Py_DECREF(func);
return res;
}
@ -6461,12 +6526,13 @@ slot_am_await(PyObject *self)
static PyObject *
slot_am_aiter(PyObject *self)
{
int unbound;
PyObject *func, *res;
_Py_IDENTIFIER(__aiter__);
func = lookup_method(self, &PyId___aiter__);
func = lookup_method(self, &PyId___aiter__, &unbound);
if (func != NULL) {
res = PyEval_CallObject(func, NULL);
res = call_unbound_noarg(unbound, func, self);
Py_DECREF(func);
return res;
}
@ -6479,12 +6545,13 @@ slot_am_aiter(PyObject *self)
static PyObject *
slot_am_anext(PyObject *self)
{
int unbound;
PyObject *func, *res;
_Py_IDENTIFIER(__anext__);
func = lookup_method(self, &PyId___anext__);
func = lookup_method(self, &PyId___anext__, &unbound);
if (func != NULL) {
res = PyEval_CallObject(func, NULL);
res = call_unbound_noarg(unbound, func, self);
Py_DECREF(func);
return res;
}