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bpo-30040: optimize inserting into empty dict (GH-12307)

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Inada Naoki 2019-03-18 20:38:33 +09:00 committed by GitHub
parent 09a9f1799c
commit 2ddc7f6d62
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1 changed files with 49 additions and 2 deletions
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51
Objects/dictobject.c
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@ -1102,6 +1102,41 @@ Fail:
return -1; return -1;
} }
// Same to insertdict but specialized for ma_keys = Py_EMPTY_KEYS.
static int
insert_to_emptydict(PyDictObject *mp, PyObject *key, Py_hash_t hash,
PyObject *value)
{
assert(mp->ma_keys == Py_EMPTY_KEYS);
PyDictKeysObject *newkeys = new_keys_object(PyDict_MINSIZE);
if (newkeys == NULL) {
return -1;
}
if (!PyUnicode_CheckExact(key)) {
newkeys->dk_lookup = lookdict;
}
dictkeys_decref(Py_EMPTY_KEYS);
mp->ma_keys = newkeys;
mp->ma_values = NULL;
Py_INCREF(key);
Py_INCREF(value);
MAINTAIN_TRACKING(mp, key, value);
size_t hashpos = (size_t)hash & (PyDict_MINSIZE-1);
PyDictKeyEntry *ep = &DK_ENTRIES(mp->ma_keys)[0];
dictkeys_set_index(mp->ma_keys, hashpos, 0);
ep->me_key = key;
ep->me_hash = hash;
ep->me_value = value;
mp->ma_used++;
mp->ma_version_tag = DICT_NEXT_VERSION();
mp->ma_keys->dk_usable--;
mp->ma_keys->dk_nentries++;
return 0;
}
/* /*
Internal routine used by dictresize() to build a hashtable of entries. Internal routine used by dictresize() to build a hashtable of entries.
*/ */
@ -1274,7 +1309,7 @@ _PyDict_NewPresized(Py_ssize_t minused)
Py_ssize_t newsize; Py_ssize_t newsize;
PyDictKeysObject *new_keys; PyDictKeysObject *new_keys;
if (minused == 0) { if (minused <= USABLE_FRACTION(PyDict_MINSIZE)) {
return PyDict_New(); return PyDict_New();
} }
/* There are no strict guarantee that returned dict can contain minused /* There are no strict guarantee that returned dict can contain minused
@ -1286,7 +1321,7 @@ _PyDict_NewPresized(Py_ssize_t minused)
} }
else { else {
Py_ssize_t minsize = ESTIMATE_SIZE(minused); Py_ssize_t minsize = ESTIMATE_SIZE(minused);
newsize = PyDict_MINSIZE; newsize = PyDict_MINSIZE*2;
while (newsize < minsize) { while (newsize < minsize) {
newsize <<= 1; newsize <<= 1;
} }
@ -1495,6 +1530,9 @@ PyDict_SetItem(PyObject *op, PyObject *key, PyObject *value)
return -1; return -1;
} }
if (mp->ma_keys == Py_EMPTY_KEYS) {
return insert_to_emptydict(mp, key, hash, value);
}
/* insertdict() handles any resizing that might be necessary */ /* insertdict() handles any resizing that might be necessary */
return insertdict(mp, key, hash, value); return insertdict(mp, key, hash, value);
} }
@ -1514,6 +1552,9 @@ _PyDict_SetItem_KnownHash(PyObject *op, PyObject *key, PyObject *value,
assert(hash != -1); assert(hash != -1);
mp = (PyDictObject *)op; mp = (PyDictObject *)op;
if (mp->ma_keys == Py_EMPTY_KEYS) {
return insert_to_emptydict(mp, key, hash, value);
}
/* insertdict() handles any resizing that might be necessary */ /* insertdict() handles any resizing that might be necessary */
return insertdict(mp, key, hash, value); return insertdict(mp, key, hash, value);
} }
@ -2844,6 +2885,12 @@ PyDict_SetDefault(PyObject *d, PyObject *key, PyObject *defaultobj)
if (hash == -1) if (hash == -1)
return NULL; return NULL;
} }
if (mp->ma_keys == Py_EMPTY_KEYS) {
if (insert_to_emptydict(mp, key, hash, defaultobj) < 0) {
return NULL;
}
return defaultobj;
}
if (mp->ma_values != NULL && !PyUnicode_CheckExact(key)) { if (mp->ma_values != NULL && !PyUnicode_CheckExact(key)) {
if (insertion_resize(mp) < 0) if (insertion_resize(mp) < 0)