Search

Issues

• Free-threaded build: deque iteration and list(deque) take a critical section per item

  python/cpython#161850 · opened on Nov 12, 2026

• inspect.getframeinfo and traceback build every preceding co_positions() tuple

  python/cpython#161799 · opened on Nov 11, 2026
  4

• Use the Neri–Schneider algorithm for ordinal-to-date conversion in datetime

  python/cpython#161746 · opened on Nov 10, 2026
  3

• Avoid stop-the-world when __abstractmethods__ does not change the abstract flag

  python/cpython#161744 · opened on Nov 10, 2026

• gh-161644: Avoid unmarshalling zipped .pyc files twice on import

  Unread
  #161700· opened Nov 9, 2026 · Updated Nov 9, 2026
  1

• gh-161676: Reduce perf trampoline overhead

  Unread
  #161677· opened Nov 9, 2026 · Updated Nov 9, 2026·Draft

• Reduce perf trampoline overhead

  python/cpython#161676 · opened on Nov 9, 2026

• json.dumps: single circle markers hash lookup

  python/cpython#161661 · opened on Nov 9, 2026
  2

• zipimport reads and unmarshals pyc's twice per import

  python/cpython#161644 · opened on Nov 8, 2026
  1

• platform: import _wmi on first use

  python/cpython#161513 · opened on Nov 6, 2026
  1

• mimetypes: reading the Windows registry through HKEY_CLASSES_ROOT is slow

  python/cpython#161512 · opened on Nov 6, 2026
  4

• Windows: avoid importing encodings._win_cp_codecs and time at startup

  python/cpython#161510 · opened on Nov 6, 2026
  3

• zlib, gzip, lzma and zstd in 3.15: decompressing large outputs is slower on macOS and Windows, and the process footprint grows on macOS (bisected to f262297)

  python/cpython#161478 · opened on Nov 6, 2026
  4

• Consider enabling tail call interpreter for sre_lib.h

  python/cpython#161469 · opened on Nov 6, 2026
  2

• Speed up _sre matching of runs of literal characters

  python/cpython#161335 · opened on Nov 4, 2026
  5

• Improve performance of exceptions

  python/cpython#161242 · opened on Nov 3, 2026
  1

• Use a managed dict for the _io types

  python/cpython#161184 · opened on Nov 2, 2026
  1

• Speed up calling an async function that doesn't suspend

  python/cpython#161170 · opened on Nov 2, 2026

• Speed up ASCII str.lower() and str.upper() (2 to 4x at 1 KB)

  python/cpython#161155 · opened on Nov 2, 2026
  4

• Speed up UTF-8 validation in tokenizer and ASCII scanning in UTF-8 decoding

  python/cpython#161145 · opened on Nov 1, 2026
  2

• Regression in re.compile() performance

  python/cpython#161125 · opened on Nov 1, 2026

• Speed up pprint on deeply nested containers

  python/cpython#161114 · opened on Nov 1, 2026

• Optimize long_bitwise: eliminate temporary allocations for negative ints and fast-path non-negative ops

  python/cpython#161075 · opened on Nov 1, 2026
  5

• Speed up tarfile.calc_chksums()

  python/cpython#160991 · opened on Oct 31, 2026
  7

• Skip the __bytes__ lookup in bytes() for exact bytes and int

  python/cpython#160931 · opened on Oct 29, 2026