gh-132657: Add maybe_enable_deferred_ref_count().

Include/internal/pycore_dict.h

@@ -114,6 +114,7 @@ extern Py_ssize_t _Py_dict_lookup_threadsafe_stackref(PyDictObject *mp, PyObject
 
 extern int _PyDict_GetMethodStackRef(PyDictObject *dict, PyObject *name, _PyStackRef *method);
 
+extern Py_ssize_t _PyDict_LookupIndexAndValue(PyDictObject *, PyObject *, PyObject **);
 extern Py_ssize_t _PyDict_LookupIndex(PyDictObject *, PyObject *);
 extern Py_ssize_t _PyDictKeys_StringLookup(PyDictKeysObject* dictkeys, PyObject *key);
 

Objects/dictobject.c

@@ -2346,10 +2346,9 @@ dict_unhashable_type(PyObject *key)
 }
 
 Py_ssize_t
-_PyDict_LookupIndex(PyDictObject *mp, PyObject *key)
+_PyDict_LookupIndexAndValue(PyDictObject *mp, PyObject *key, PyObject **value)
 {
     // TODO: Thread safety
-    PyObject *value;
     assert(PyDict_CheckExact((PyObject*)mp));
     assert(PyUnicode_CheckExact(key));
 
@@ -2359,7 +2358,14 @@ _PyDict_LookupIndex(PyDictObject *mp, PyObject *key)
         return -1;
     }
 
-    return _Py_dict_lookup(mp, key, hash, &value);
+    return _Py_dict_lookup(mp, key, hash, value);
+}
+
+Py_ssize_t
+_PyDict_LookupIndex(PyDictObject *mp, PyObject *key)
+{
+    PyObject *value; // discarded
+    return _PyDict_LookupIndexAndValue(mp, key, &value);
 }
 
 /* Same as PyDict_GetItemWithError() but with hash supplied by caller.

Python/specialize.c

@@ -355,6 +355,17 @@ static int function_kind(PyCodeObject *code);
 static bool function_check_args(PyObject *o, int expected_argcount, int opcode);
 static uint32_t function_get_version(PyObject *o, int opcode);
 
+#ifdef Py_GIL_DISABLED
+static void
+maybe_enable_deferred_ref_count(PyObject *op)
+{
+    if (!_Py_IsOwnedByCurrentThread(op)) {
+        PyUnstable_Object_EnableDeferredRefcount(op);
+    }
+}
+#endif
+
+
 static int
 specialize_module_load_attr_lock_held(PyDictObject *dict, _Py_CODEUNIT *instr, PyObject *name)
 {
@@ -369,7 +380,8 @@ specialize_module_load_attr_lock_held(PyDictObject *dict, _Py_CODEUNIT *instr, P
         SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_ATTR_MODULE_ATTR_NOT_FOUND);
         return -1;
     }
-    index = _PyDict_LookupIndex(dict, name);
+    PyObject *value;
+    index = _PyDict_LookupIndexAndValue(dict, name, &value);
     assert (index != DKIX_ERROR);
     if (index != (uint16_t)index) {
         SPECIALIZATION_FAIL(LOAD_ATTR,
@@ -384,6 +396,9 @@ specialize_module_load_attr_lock_held(PyDictObject *dict, _Py_CODEUNIT *instr, P
         SPECIALIZATION_FAIL(LOAD_ATTR, SPEC_FAIL_OUT_OF_VERSIONS);
         return -1;
     }
+#ifdef Py_GIL_DISABLED
+    maybe_enable_deferred_ref_count(value);
+#endif
     write_u32(cache->version, keys_version);
     cache->index = (uint16_t)index;
     specialize(instr, LOAD_ATTR_MODULE);
@@ -1264,7 +1279,6 @@ specialize_attr_loadclassattr(PyObject *owner, _Py_CODEUNIT *instr,
     return 1;
 }
 
-
 static void
 specialize_load_global_lock_held(
     PyObject *globals, PyObject *builtins,
@@ -1284,7 +1298,12 @@ specialize_load_global_lock_held(
         SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_LOAD_GLOBAL_NON_STRING_OR_SPLIT);
         goto fail;
     }
+#ifdef Py_GIL_DISABLED
+    PyObject *value;
+    Py_ssize_t index = _PyDict_LookupIndexAndValue((PyDictObject *)globals, name, &value);
+#else
     Py_ssize_t index = _PyDictKeys_StringLookup(globals_keys, name);
+#endif
     if (index == DKIX_ERROR) {
         SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_EXPECTED_ERROR);
         goto fail;
@@ -1305,6 +1324,9 @@ specialize_load_global_lock_held(
             SPECIALIZATION_FAIL(LOAD_GLOBAL, SPEC_FAIL_OUT_OF_RANGE);
             goto fail;
         }
+#ifdef Py_GIL_DISABLED
+        maybe_enable_deferred_ref_count(value);
+#endif
         cache->index = (uint16_t)index;
         cache->module_keys_version = (uint16_t)keys_version;
         specialize(instr, LOAD_GLOBAL_MODULE);

Tools/ftscalingbench/ftscalingbench.py

@@ -21,6 +21,7 @@
 # > echo "0" | sudo tee /sys/devices/system/cpu/cpufreq/boost
 #
 
+import copy
 import math
 import os
 import queue
@@ -214,6 +215,14 @@ def instantiate_dataclass():
     for _ in range(1000 * WORK_SCALE):
         obj = MyDataClass(x=1, y=2, z=3)
 
+
+@register_benchmark
+def deepcopy():
+    x = {'list': [1, 2], 'tuple': (1, None)}
+    for i in range(40 * WORK_SCALE):
+        copy.deepcopy(x)
+
+
 def bench_one_thread(func):
     t0 = time.perf_counter_ns()
     func()