bpo-42093: Add opcode cache for LOAD_ATTR (GH-22803)

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Pablo Galindo 2020-10-20 06:22:44 +01:00 committed by GitHub
parent 871934d4cf
commit 109826c850
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GPG key ID: 4AEE18F83AFDEB23
7 changed files with 296 additions and 7 deletions

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@ -111,6 +111,7 @@ static long dxp[256];
#else
#define OPCACHE_MIN_RUNS 1024 /* create opcache when code executed this time */
#endif
#define OPCODE_CACHE_MAX_TRIES 20
#define OPCACHE_STATS 0 /* Enable stats */
#if OPCACHE_STATS
@ -120,6 +121,12 @@ static size_t opcache_code_objects_extra_mem = 0;
static size_t opcache_global_opts = 0;
static size_t opcache_global_hits = 0;
static size_t opcache_global_misses = 0;
static size_t opcache_attr_opts = 0;
static size_t opcache_attr_hits = 0;
static size_t opcache_attr_misses = 0;
static size_t opcache_attr_deopts = 0;
static size_t opcache_attr_total = 0;
#endif
@ -365,6 +372,25 @@ _PyEval_Fini(void)
opcache_global_opts);
fprintf(stderr, "\n");
fprintf(stderr, "-- Opcode cache LOAD_ATTR hits = %zd (%d%%)\n",
opcache_attr_hits,
(int) (100.0 * opcache_attr_hits /
opcache_attr_total));
fprintf(stderr, "-- Opcode cache LOAD_ATTR misses = %zd (%d%%)\n",
opcache_attr_misses,
(int) (100.0 * opcache_attr_misses /
opcache_attr_total));
fprintf(stderr, "-- Opcode cache LOAD_ATTR opts = %zd\n",
opcache_attr_opts);
fprintf(stderr, "-- Opcode cache LOAD_ATTR deopts = %zd\n",
opcache_attr_deopts);
fprintf(stderr, "-- Opcode cache LOAD_ATTR total = %zd\n",
opcache_attr_total);
#endif
}
@ -1224,16 +1250,43 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)
do { \
co_opcache = NULL; \
if (co->co_opcache != NULL) { \
unsigned char co_opt_offset = \
unsigned char co_opcache_offset = \
co->co_opcache_map[next_instr - first_instr]; \
if (co_opt_offset > 0) { \
assert(co_opt_offset <= co->co_opcache_size); \
co_opcache = &co->co_opcache[co_opt_offset - 1]; \
if (co_opcache_offset > 0) { \
assert(co_opcache_offset <= co->co_opcache_size); \
co_opcache = &co->co_opcache[co_opcache_offset - 1]; \
assert(co_opcache != NULL); \
} \
} \
} while (0)
#define OPCACHE_DEOPT() \
do { \
if (co_opcache != NULL) { \
co_opcache->optimized = -1; \
unsigned char co_opcache_offset = \
co->co_opcache_map[next_instr - first_instr]; \
assert(co_opcache_offset <= co->co_opcache_size); \
co->co_opcache_map[co_opcache_offset] = 0; \
co_opcache = NULL; \
} \
} while (0)
#define OPCACHE_DEOPT_LOAD_ATTR() \
do { \
if (co_opcache != NULL) { \
OPCACHE_STAT_ATTR_DEOPT(); \
OPCACHE_DEOPT(); \
} \
} while (0)
#define OPCACHE_MAYBE_DEOPT_LOAD_ATTR() \
do { \
if (co_opcache != NULL && --co_opcache->optimized <= 0) { \
OPCACHE_DEOPT_LOAD_ATTR(); \
} \
} while (0)
#if OPCACHE_STATS
#define OPCACHE_STAT_GLOBAL_HIT() \
@ -1251,12 +1304,43 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, PyFrameObject *f, int throwflag)
if (co->co_opcache != NULL) opcache_global_opts++; \
} while (0)
#define OPCACHE_STAT_ATTR_HIT() \
do { \
if (co->co_opcache != NULL) opcache_attr_hits++; \
} while (0)
#define OPCACHE_STAT_ATTR_MISS() \
do { \
if (co->co_opcache != NULL) opcache_attr_misses++; \
} while (0)
#define OPCACHE_STAT_ATTR_OPT() \
do { \
if (co->co_opcache!= NULL) opcache_attr_opts++; \
} while (0)
#define OPCACHE_STAT_ATTR_DEOPT() \
do { \
if (co->co_opcache != NULL) opcache_attr_deopts++; \
} while (0)
#define OPCACHE_STAT_ATTR_TOTAL() \
do { \
if (co->co_opcache != NULL) opcache_attr_total++; \
} while (0)
#else /* OPCACHE_STATS */
#define OPCACHE_STAT_GLOBAL_HIT()
#define OPCACHE_STAT_GLOBAL_MISS()
#define OPCACHE_STAT_GLOBAL_OPT()
#define OPCACHE_STAT_ATTR_HIT()
#define OPCACHE_STAT_ATTR_MISS()
#define OPCACHE_STAT_ATTR_OPT()
#define OPCACHE_STAT_ATTR_DEOPT()
#define OPCACHE_STAT_ATTR_TOTAL()
#endif
/* Start of code */
@ -3023,7 +3107,134 @@ main_loop:
case TARGET(LOAD_ATTR): {
PyObject *name = GETITEM(names, oparg);
PyObject *owner = TOP();
PyObject *res = PyObject_GetAttr(owner, name);
PyTypeObject *type = Py_TYPE(owner);
PyObject *res;
PyObject **dictptr;
PyObject *dict;
_PyOpCodeOpt_LoadAttr *la;
OPCACHE_STAT_ATTR_TOTAL();
OPCACHE_CHECK();
if (co_opcache != NULL && PyType_HasFeature(type, Py_TPFLAGS_VALID_VERSION_TAG))
{
if (co_opcache->optimized > 0) {
/* Fast path -- cache hit makes LOAD_ATTR ~30% faster */
la = &co_opcache->u.la;
if (la->type == type && la->tp_version_tag == type->tp_version_tag)
{
assert(type->tp_dict != NULL);
assert(type->tp_dictoffset > 0);
dictptr = (PyObject **) ((char *)owner + type->tp_dictoffset);
dict = *dictptr;
if (dict != NULL && PyDict_CheckExact(dict)) {
Py_ssize_t hint = la->hint;
Py_INCREF(dict);
res = NULL;
la->hint = _PyDict_GetItemHint((PyDictObject*)dict, name, hint, &res);
if (res != NULL) {
if (la->hint == hint && hint >= 0) {
/* Our hint has helped -- cache hit. */
OPCACHE_STAT_ATTR_HIT();
} else {
/* The hint we provided didn't work.
Maybe next time? */
OPCACHE_MAYBE_DEOPT_LOAD_ATTR();
}
Py_INCREF(res);
SET_TOP(res);
Py_DECREF(owner);
Py_DECREF(dict);
DISPATCH();
} else {
// This attribute can be missing sometimes -- we
// don't want to optimize this lookup.
OPCACHE_DEOPT_LOAD_ATTR();
Py_DECREF(dict);
}
} else {
// There is no dict, or __dict__ doesn't satisfy PyDict_CheckExact
OPCACHE_DEOPT_LOAD_ATTR();
}
} else {
// The type of the object has either been updated,
// or is different. Maybe it will stabilize?
OPCACHE_MAYBE_DEOPT_LOAD_ATTR();
}
OPCACHE_STAT_ATTR_MISS();
}
if (co_opcache != NULL && /* co_opcache can be NULL after a DEOPT() call. */
type->tp_getattro == PyObject_GenericGetAttr)
{
PyObject *descr;
Py_ssize_t ret;
if (type->tp_dictoffset > 0) {
if (type->tp_dict == NULL) {
if (PyType_Ready(type) < 0) {
Py_DECREF(owner);
SET_TOP(NULL);
goto error;
}
}
descr = _PyType_Lookup(type, name);
if (descr == NULL ||
descr->ob_type->tp_descr_get == NULL ||
!PyDescr_IsData(descr))
{
dictptr = (PyObject **) ((char *)owner + type->tp_dictoffset);
dict = *dictptr;
if (dict != NULL && PyDict_CheckExact(dict)) {
Py_INCREF(dict);
res = NULL;
ret = _PyDict_GetItemHint((PyDictObject*)dict, name, -1, &res);
if (res != NULL) {
Py_INCREF(res);
Py_DECREF(dict);
Py_DECREF(owner);
SET_TOP(res);
if (co_opcache->optimized == 0) {
// First time we optimize this opcode. */
OPCACHE_STAT_ATTR_OPT();
co_opcache->optimized = OPCODE_CACHE_MAX_TRIES;
}
la = &co_opcache->u.la;
la->type = type;
la->tp_version_tag = type->tp_version_tag;
la->hint = ret;
DISPATCH();
}
Py_DECREF(dict);
} else {
// There is no dict, or __dict__ doesn't satisfy PyDict_CheckExact
OPCACHE_DEOPT_LOAD_ATTR();
}
} else {
// We failed to find an attribute without a data-like descriptor
OPCACHE_DEOPT_LOAD_ATTR();
}
} else {
// The object's class does not have a tp_dictoffset we can use
OPCACHE_DEOPT_LOAD_ATTR();
}
} else if (type->tp_getattro != PyObject_GenericGetAttr) {
OPCACHE_DEOPT_LOAD_ATTR();
}
}
/* slow path */
res = PyObject_GetAttr(owner, name);
Py_DECREF(owner);
SET_TOP(res);
if (res == NULL)