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gvanrossumgvanrossum
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*EXPERIMENTAL* speedup of slot_sq_item. This sped up the following
test dramatically: class T(tuple): __dynamic__ = 1 t = T(range(1000)) for i in range(1000): tt = tuple(t) The speedup was about 5x compared to the previous state of CVS (1.7 vs. 8.8, in arbitrary time units). But it's still more than twice as slow as as the same test with __dynamic__ = 0 (0.8). I'm not sure that I really want to go through the trouble of this kind of speedup for every slot. Even doing it just for the most popular slots will be a major effort (the new slot_sq_item is 40+ lines, while the old one was one line with a powerful macro -- unfortunately the speedup comes from expanding the macro and doing things in a way specific to the slot signature). An alternative that I'm currently considering is sketched in PLAN.txt: trap setattr on type objects. But this will require keeping track of all derived types using weak references.
1 parent 1b0e549 commit f4593e0

3 files changed

Lines changed: 96 additions & 40 deletions

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‎Include/descrobject.h‎

Lines changed: 34 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -20,6 +20,40 @@ struct wrapperbase {
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char *doc;
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};
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/* Various kinds of descriptor objects */
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25+
#define PyDescr_COMMON \
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PyObject_HEAD \
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PyTypeObject *d_type; \
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PyObject *d_name
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30+
typedef struct {
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PyDescr_COMMON;
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} PyDescrObject;
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34+
typedef struct {
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PyDescr_COMMON;
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PyMethodDef *d_method;
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} PyMethodDescrObject;
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typedef struct {
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PyDescr_COMMON;
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struct PyMemberDef *d_member;
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} PyMemberDescrObject;
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typedef struct {
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PyDescr_COMMON;
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PyGetSetDef *d_getset;
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} PyGetSetDescrObject;
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typedef struct {
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PyDescr_COMMON;
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struct wrapperbase *d_base;
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void *d_wrapped; /* This can be any function pointer */
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} PyWrapperDescrObject;
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extern DL_IMPORT(PyTypeObject) PyWrapperDescr_Type;
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2357
extern DL_IMPORT(PyObject *) PyDescr_NewMethod(PyTypeObject *, PyMethodDef *);
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extern DL_IMPORT(PyObject *) PyDescr_NewMember(PyTypeObject *,
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struct PyMemberDef *);

‎Objects/descrobject.c‎

Lines changed: 1 addition & 33 deletions
Original file line numberDiff line numberDiff line change
@@ -3,38 +3,6 @@
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#include "Python.h"
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#include "structmember.h" /* Why is this not included in Python.h? */
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6-
/* Various kinds of descriptor objects */
7-
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#define COMMON \
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PyObject_HEAD \
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PyTypeObject *d_type; \
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PyObject *d_name
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typedef struct {
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COMMON;
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} PyDescrObject;
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typedef struct {
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COMMON;
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PyMethodDef *d_method;
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} PyMethodDescrObject;
21-
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typedef struct {
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COMMON;
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PyMemberDef *d_member;
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} PyMemberDescrObject;
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typedef struct {
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COMMON;
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PyGetSetDef *d_getset;
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} PyGetSetDescrObject;
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typedef struct {
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COMMON;
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struct wrapperbase *d_base;
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void *d_wrapped; /* This can be any function pointer */
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} PyWrapperDescrObject;
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static void
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descr_dealloc(PyDescrObject *descr)
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{
@@ -481,7 +449,7 @@ static PyTypeObject PyGetSetDescr_Type = {
481449
(descrsetfunc)getset_set, /* tp_descr_set */
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};
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484-
static PyTypeObject PyWrapperDescr_Type = {
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PyTypeObject PyWrapperDescr_Type = {
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PyObject_HEAD_INIT(&PyType_Type)
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0,
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"wrapper_descriptor",

‎Objects/typeobject.c‎

Lines changed: 61 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -2113,12 +2113,16 @@ wrap_sq_item(PyObject *self, PyObject *args, void *wrapped)
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PyObject *arg;
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int i;
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2116-
if (!PyArg_ParseTuple(args, "O", &arg))
2117-
return NULL;
2118-
i = getindex(self, arg);
2119-
if (i == -1 && PyErr_Occurred())
2120-
return NULL;
2121-
return (*func)(self, i);
2116+
if (PyTuple_GET_SIZE(args) == 1) {
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arg = PyTuple_GET_ITEM(args, 0);
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i = getindex(self, arg);
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if (i == -1 && PyErr_Occurred())
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return NULL;
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return (*func)(self, i);
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}
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PyArg_ParseTuple(args, "O", &arg);
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assert(PyErr_Occurred());
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return NULL;
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}
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21242128
static struct wrapperbase tab_getitem_int[] = {
@@ -2825,7 +2829,57 @@ slot_sq_length(PyObject *self)
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28262830
SLOT1(slot_sq_concat, "__add__", PyObject *, "O")
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SLOT1(slot_sq_repeat, "__mul__", int, "i")
2828-
SLOT1(slot_sq_item, "__getitem__", int, "i")
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/* Super-optimized version of slot_sq_item.
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Other slots could do the same... */
2835+
static PyObject *
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slot_sq_item(PyObject *self, int i)
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{
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static PyObject *getitem_str;
2839+
PyObject *func, *args = NULL, *ival = NULL, *retval = NULL;
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descrgetfunc f;
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2842+
if (getitem_str == NULL) {
2843+
getitem_str = PyString_InternFromString("__getitem__");
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if (getitem_str == NULL)
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return NULL;
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}
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func = _PyType_Lookup(self->ob_type, getitem_str);
2848+
if (func != NULL) {
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if (func->ob_type == &PyWrapperDescr_Type) {
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PyWrapperDescrObject *wrapper =
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(PyWrapperDescrObject *)func;
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if (wrapper->d_base->wrapper == wrap_sq_item) {
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intargfunc f;
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f = (intargfunc)(wrapper->d_wrapped);
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return f(self, i);
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}
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}
2858+
if ((f = func->ob_type->tp_descr_get) == NULL)
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Py_INCREF(func);
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else
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func = f(func, self, (PyObject *)(self->ob_type));
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ival = PyInt_FromLong(i);
2863+
if (ival != NULL) {
2864+
args = PyTuple_New(1);
2865+
if (args != NULL) {
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PyTuple_SET_ITEM(args, 0, ival);
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retval = PyObject_Call(func, args, NULL);
2868+
Py_XDECREF(args);
2869+
Py_XDECREF(func);
2870+
return retval;
2871+
}
2872+
}
2873+
}
2874+
else {
2875+
PyErr_SetObject(PyExc_AttributeError, getitem_str);
2876+
}
2877+
Py_XDECREF(args);
2878+
Py_XDECREF(ival);
2879+
Py_XDECREF(func);
2880+
return NULL;
2881+
}
2882+
28292883
SLOT2(slot_sq_slice, "__getslice__", int, int, "ii")
28302884

28312885
static int

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