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bpo-40602: Optimize _Py_hashtable_get_ptr() (GH-20066)

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_Py_hashtable_get_entry_ptr() avoids comparing the entry hash:
compare directly keys.

Move _Py_hashtable_get_entry_ptr() just after
_Py_hashtable_get_entry_generic().
This commit is contained in:
Victor Stinner 2020-05-13 05:36:23 +02:00 • committed by GitHub
parent 5b0a30354d
commit 42bae3a3d9
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1 changed files with 23 additions and 24 deletions
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47
Python/hashtable.c
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@ -193,6 +193,29 @@ _Py_hashtable_get_entry_generic(_Py_hashtable_t *ht, const void *key)
}
// Specialized for:
// hash_func == _Py_hashtable_hash_ptr
// compare_func == _Py_hashtable_compare_direct
static _Py_hashtable_entry_t *
_Py_hashtable_get_entry_ptr(_Py_hashtable_t *ht, const void *key)
{
Py_uhash_t key_hash = _Py_hashtable_hash_ptr(key);
size_t index = key_hash & (ht->num_buckets - 1);
_Py_hashtable_entry_t *entry = entry = TABLE_HEAD(ht, index);
while (1) {
if (entry == NULL) {
return NULL;
}
// Compare directly keys (ignore entry->key_hash)
if (entry->key == key) {
break;
}
entry = ENTRY_NEXT(entry);
}
return entry;
}
void*
_Py_hashtable_steal(_Py_hashtable_t *ht, const void *key)
{
@ -275,30 +298,6 @@ _Py_hashtable_get(_Py_hashtable_t *ht, const void *key)
}
// Specialized for:
// hash_func == _Py_hashtable_hash_ptr
// compare_func == _Py_hashtable_compare_direct
_Py_hashtable_entry_t *
_Py_hashtable_get_entry_ptr(_Py_hashtable_t *ht, const void *key)
{
Py_uhash_t key_hash = _Py_hashtable_hash_ptr(key);
size_t index = key_hash & (ht->num_buckets - 1);
_Py_hashtable_entry_t *entry = entry = TABLE_HEAD(ht, index);
while (1) {
if (entry == NULL) {
return NULL;
}
if (entry->key_hash == key_hash) {
if (entry->key == key) {
break;
}
}
entry = ENTRY_NEXT(entry);
}
return entry;
}
int
_Py_hashtable_foreach(_Py_hashtable_t *ht,
_Py_hashtable_foreach_func func,