8000 gh-95913: Edit & expand Optimizations in 3.11 WhatsNew (#98426) · python/cpython@f58631b · GitHub
[go: up one dir, main page]

Skip to content

Commit f58631b

Browse files
authored
gh-95913: Edit & expand Optimizations in 3.11 WhatsNew (#98426)
1 parent 8f30267 commit f58631b

File tree

1 file changed

+39
-20
lines changed

1 file changed

+39
-20
lines changed

Doc/whatsnew/3.11.rst

Lines changed: 39 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -1171,33 +1171,52 @@ fcntl
11711171
Optimizations
11721172
=============
11731173

1174-
* Compiler now optimizes simple C-style formatting with literal format
1175-
containing only format codes ``%s``, ``%r`` and ``%a`` and makes it as
1176-
fast as corresponding f-string expression.
1174+
This section covers specific optimizations independent of the
1175+
:ref:`whatsnew311-faster-cpython` project, which is covered in its own section.
1176+
1177+
* The compiler now optimizes simple
1178+
:ref:`printf-style % formatting <old-string-formatting>` on string literals
1179+
containing only the format codes ``%s``, ``%r`` and ``%a`` and makes it as
1180+
fast as a corresponding :term:`f-string` expression.
11771181
(Contributed by Serhiy Storchaka in :issue:`28307`.)
11781182

1179-
* "Zero-cost" exceptions are implemented. The cost of ``try`` statements is
1180-
almost eliminated when no exception is raised.
1181-
(Contributed by Mark Shannon in :issue:`40222`.)
1183+
* Integer division (``//``) is better tuned for optimization by compilers.
1184+
It is now around 20% faster on x86-64 when dividing an :class:`int`
1185+
by a value smaller than ``2**30``.
1186+
(Contributed by Gregory P. Smith and Tim Peters in :gh:`90564`.)
11821187

1183-
* Pure ASCII strings are now normalized in constant time by :func:`unicodedata.normalize`.
1184-
(Contributed by Dong-hee Na in :issue:`44987`.)
1188+
* :func:`sum` is now nearly 30% faster for integers smaller than ``2**30``.
1189+
(Contributed by Stefan Behnel in :gh:`68264`.)
11851190

1186-
* :mod:`math` functions :func:`~math.comb` and :func:`~math.perm` are now up
1187-
to 10 times or more faster for large arguments (the speed up is larger for
1188-
larger *k*).
1189-
(Contributed by Serhiy Storchaka in :issue:`37295`.)
1191+
* Resizing lists is streamlined for the common case,
1192+
speeding up :meth:`list.append` by ≈15%
1193+
and simple :term:`list comprehension`\s by up to 20-30%
1194+
(Contributed by Dennis Sweeney in :gh:`91165`.)
11901195

1191-
* Dict don't store hash value when all inserted keys are Unicode objects.
1192-
This reduces dict size. For example, ``sys.getsizeof(dict.fromkeys("abcdefg"))``
1193-
becomes 272 bytes from 352 bytes on 64bit platform.
1196+
* Dictionaries don't store hash values when all keys are Unicode objects,
1197+
decreasing :class:`dict` size.
1198+
For example, ``sys.getsizeof(dict.fromkeys("abcdefg"))``
1199+
is reduced from 352 bytes to 272 bytes (23% smaller) on 64-bit platforms.
11941200
(Contributed by Inada Naoki in :issue:`46845`.)
11951201

1196-
* :mod:`re`'s regular expression matching engine has been partially refactored,
1197-
and now uses computed gotos (or "threaded code") on supported platforms. As a
1198-
result, Python 3.11 executes the `pyperformance regular expression benchmarks
1199-
<https://pyperformance.readthedocs.io/benchmarks.html#regex-dna>`_ up to 10%
1200-
faster than Python 3.10.
1202+
* Using :class:`asyncio.DatagramProtocol` is now orders of magnitude faster
1203+
when transferring large files over UDP,
1204+
with speeds over 100 times higher for a ≈60 MiB file.
1205+
(Contributed by msoxzw in :gh:`91487`.)
1206+
1207+
* :mod:`math` functions :func:`~math.comb` and :func:`~math.perm` are now
1208+
≈10 times faster for large arguments (with a larger speedup for larger *k*).
1209+
(Contributed by Serhiy Storchaka in :issue:`37295`.)
1210+
1211+
* The :mod:`statistics` functions :func:`~statistics.mean`,
1212+
:func:`~statistics.variance` and :func:`~statistics.stdev` now consume
1213+
iterators in one pass rather than converting them to a :class:`list` first.
1214+
This is twice as fast and can save substantial memory.
1215+
(Contributed by Raymond Hettinger in :gh:`90415`.)
1216+
1217+
* :func:`unicodedata.normalize`
1218+
now normalizes pure-ASCII strings in constant time.
1219+
(Contributed by Dong-hee Na in :issue:`44987`.)
12011220

12021221

12031222
.. _whatsnew311-faster-cpython:

0 commit comments

Comments
 (0)
0