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-rw-r--r--Doc/whatsnew/3.8.rst55
1 files changed, 52 insertions, 3 deletions
diff --git a/Doc/whatsnew/3.8.rst b/Doc/whatsnew/3.8.rst
index e267096..8338cb6 100644
--- a/Doc/whatsnew/3.8.rst
+++ b/Doc/whatsnew/3.8.rst
@@ -2152,6 +2152,55 @@ CPython bytecode changes
Demos and Tools
---------------
-* Added a benchmark script for timing various ways to access variables:
- ``Tools/scripts/var_access_benchmark.py``.
- (Contributed by Raymond Hettinger in :issue:`35884`.)
+Added a benchmark script for timing various ways to access variables:
+``Tools/scripts/var_access_benchmark.py``.
+(Contributed by Raymond Hettinger in :issue:`35884`.)
+
+Here's a summary of performance improvements since Python 3.3:
+
+.. code-block:: none
+
+ Python version 3.3 3.4 3.5 3.6 3.7 3.8
+ -------------- --- --- --- --- --- ---
+
+ Variable and attribute read access:
+ read_local 4.0 7.1 7.1 5.4 5.1 3.9
+ read_nonlocal 5.3 7.1 8.1 5.8 5.4 4.4
+ read_global 13.3 15.5 19.0 14.3 13.6 7.6
+ read_builtin 20.0 21.1 21.6 18.5 19.0 7.5
+ read_classvar_from_class 20.5 25.6 26.5 20.7 19.5 18.4
+ read_classvar_from_instance 18.5 22.8 23.5 18.8 17.1 16.4
+ read_instancevar 26.8 32.4 33.1 28.0 26.3 25.4
+ read_instancevar_slots 23.7 27.8 31.3 20.8 20.8 20.2
+ read_namedtuple 68.5 73.8 57.5 45.0 46.8 18.4
+ read_boundmethod 29.8 37.6 37.9 29.6 26.9 27.7
+
+ Variable and attribute write access:
+ write_local 4.6 8.7 9.3 5.5 5.3 4.3
+ write_nonlocal 7.3 10.5 11.1 5.6 5.5 4.7
+ write_global 15.9 19.7 21.2 18.0 18.0 15.8
+ write_classvar 81.9 92.9 96.0 104.6 102.1 39.2
+ write_instancevar 36.4 44.6 45.8 40.0 38.9 35.5
+ write_instancevar_slots 28.7 35.6 36.1 27.3 26.6 25.7
+
+ Data structure read access:
+ read_list 19.2 24.2 24.5 20.8 20.8 19.0
+ read_deque 19.9 24.7 25.5 20.2 20.6 19.8
+ read_dict 19.7 24.3 25.7 22.3 23.0 21.0
+ read_strdict 17.9 22.6 24.3 19.5 21.2 18.9
+
+ Data structure write access:
+ write_list 21.2 27.1 28.5 22.5 21.6 20.0
+ write_deque 23.8 28.7 30.1 22.7 21.8 23.5
+ write_dict 25.9 31.4 33.3 29.3 29.2 24.7
+ write_strdict 22.9 28.4 29.9 27.5 25.2 23.1
+
+ Stack (or queue) operations:
+ list_append_pop 144.2 93.4 112.7 75.4 74.2 50.8
+ deque_append_pop 30.4 43.5 57.0 49.4 49.2 42.5
+ deque_append_popleft 30.8 43.7 57.3 49.7 49.7 42.8
+
+ Timing loop:
+ loop_overhead 0.3 0.5 0.6 0.4 0.3 0.3
+
+ (Measured from the macOS 64-bit builds found at python.org)