From 93707a39a6558af7bcaa2a2e47bf08f7a9e93b84 Mon Sep 17 00:00:00 2001 From: INADA Naoki Date: Tue, 11 Apr 2017 18:39:34 +0900 Subject: [PATCH 1/6] bpo-30040: New empty dict uses key-sharing dict. Like dict.clear(). Sizeof new empty dict becomes 72 bytes from 240 bytes (amd64). --- Objects/dictobject.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/Objects/dictobject.c b/Objects/dictobject.c index 83cadda84c6dc4c..a67143090e8789a 100644 --- a/Objects/dictobject.c +++ b/Objects/dictobject.c @@ -691,10 +691,8 @@ clone_combined_dict(PyDictObject *orig) PyObject * PyDict_New(void) { - PyDictKeysObject *keys = new_keys_object(PyDict_MINSIZE); - if (keys == NULL) - return NULL; - return new_dict(keys, NULL); + DK_INCREF(Py_EMPTY_KEYS); + return new_dict(Py_EMPTY_KEYS, empty_values); } /* Search index of hash table from offset of entry table */ @@ -1276,6 +1274,9 @@ _PyDict_NewPresized(Py_ssize_t minused) Py_ssize_t newsize; PyDictKeysObject *new_keys; + if (minused == 0) { + return PyDict_New(); + } /* There are no strict guarantee that returned dict can contain minused * items without resize. So we create medium size dict instead of very * large dict or MemoryError. From ede0819c3af4f08e2c07a608db8002b929b03b44 Mon Sep 17 00:00:00 2001 From: INADA Naoki Date: Tue, 11 Apr 2017 18:53:28 +0900 Subject: [PATCH 2/6] fix SizeofTest --- Lib/test/test_sys.py | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py index 92aefd8d7af44be..4bd54af3629c882 100644 --- a/Lib/test/test_sys.py +++ b/Lib/test/test_sys.py @@ -982,8 +982,10 @@ def inner(): check(int.__add__, size('3P2P')) # method-wrapper (descriptor object) check({}.__iter__, size('2P')) + # empty dict + check({}, size('nQ2P')) # dict - check({}, size('nQ2P') + calcsize('2nP2n') + 8 + (8*2//3)*calcsize('n2P')) + check({"a": 1}, size('nQ2P') + calcsize('2nP2n') + 8 + (8*2//3)*calcsize('n2P')) longdict = {1:1, 2:2, 3:3, 4:4, 5:5, 6:6, 7:7, 8:8} check(longdict, size('nQ2P') + calcsize('2nP2n') + 16 + (16*2//3)*calcsize('n2P')) # dictionary-keyview From 5d6db25d92b3f192ff910444d83b02b52695a382 Mon Sep 17 00:00:00 2001 From: INADA Naoki Date: Tue, 11 Apr 2017 19:21:30 +0900 Subject: [PATCH 3/6] fix SharedKeyTests --- Lib/test/test_descr.py | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py index fc885c5e62f2520..0582aa026c17ca8 100644 --- a/Lib/test/test_descr.py +++ b/Lib/test/test_descr.py @@ -5346,7 +5346,7 @@ class B(A): a, b = A(), B() self.assertEqual(sys.getsizeof(vars(a)), sys.getsizeof(vars(b))) - self.assertLess(sys.getsizeof(vars(a)), sys.getsizeof({})) + self.assertLess(sys.getsizeof(vars(a)), sys.getsizeof({"a":1})) # Initial hash table can contain at most 5 elements. # Set 6 attributes to cause internal resizing. a.x, a.y, a.z, a.w, a.v, a.u = range(6) From b8cbfc77d6752bc74eed9fc4a79d3eacdc32cc13 Mon Sep 17 00:00:00 2001 From: Carl Bordum Hansen Date: Mon, 4 Mar 2019 21:41:00 +0100 Subject: [PATCH 4/6] bpo-30040: new comparison for shared key subclass test As suggested by Mark Shannon in the GitHub review. --- Lib/test/test_descr.py | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py index 0582aa026c17ca8..e39fea615db3505 100644 --- a/Lib/test/test_descr.py +++ b/Lib/test/test_descr.py @@ -5353,9 +5353,9 @@ class B(A): self.assertNotEqual(sys.getsizeof(vars(a)), sys.getsizeof(vars(b))) a2 = A() self.assertEqual(sys.getsizeof(vars(a)), sys.getsizeof(vars(a2))) - self.assertLess(sys.getsizeof(vars(a)), sys.getsizeof({})) + self.assertLess(sys.getsizeof(vars(a)), sys.getsizeof({"a":1})) b.u, b.v, b.w, b.t, b.s, b.r = range(6) - self.assertLess(sys.getsizeof(vars(b)), sys.getsizeof({})) + self.assertLess(sys.getsizeof(vars(b)), sys.getsizeof({"a":1})) class DebugHelperMeta(type): From 780b07719c80a5da430f01727318df9498a7adac Mon Sep 17 00:00:00 2001 From: Inada Naoki Date: Fri, 8 Mar 2019 18:31:54 +0900 Subject: [PATCH 5/6] fix --- Objects/dictobject.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Objects/dictobject.c b/Objects/dictobject.c index a67143090e8789a..108c6128ab1acbc 100644 --- a/Objects/dictobject.c +++ b/Objects/dictobject.c @@ -691,7 +691,7 @@ clone_combined_dict(PyDictObject *orig) PyObject * PyDict_New(void) { - DK_INCREF(Py_EMPTY_KEYS); + dictkeys_incref(Py_EMPTY_KEYS); return new_dict(Py_EMPTY_KEYS, empty_values); } From 22ca2e312e730481e1509e7e157bc8235e7f8985 Mon Sep 17 00:00:00 2001 From: Inada Naoki Date: Mon, 11 Mar 2019 22:31:01 +0900 Subject: [PATCH 6/6] Add NEWS entry --- .../Core and Builtins/2019-03-11-22-30-56.bpo-30040.W9z8X7.rst | 2 ++ 1 file changed, 2 insertions(+) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2019-03-11-22-30-56.bpo-30040.W9z8X7.rst diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-03-11-22-30-56.bpo-30040.W9z8X7.rst b/Misc/NEWS.d/next/Core and Builtins/2019-03-11-22-30-56.bpo-30040.W9z8X7.rst new file mode 100644 index 000000000000000..eacba679d5a3a4d --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2019-03-11-22-30-56.bpo-30040.W9z8X7.rst @@ -0,0 +1,2 @@ +New empty dict uses fewer memory for now. It used more memory than empty +dict created by ``dict.clear()``. Patch by Inada Naoki.