[New-bugs-announce] [issue41006] Reduce number of modules imported by runpy

[STINNER Victor]

New submission from STINNER Victor <vstinner at python.org>:

Currently, the runpy module imports many modules. runpy is used by "python3 -m module". I propose to attempt to reduce the number of imports to reduce Python startup time.


With my local changes, I reduce Python startup time from 24 ms to 18 ms:

Mean +- std dev: [ref] 24.3 ms +- 0.2 ms -> [patch] 18.0 ms +- 0.3 ms: 1.35x faster (-26%)

Timing measured by:

  ./python -m venv env
  python -m pyperf command -v -o patch.json -- env/bin/python -m empty


Currently, runpy imports +21 modules:

* ./python mod.py: Total 33
* ./python -m mod: Total 54 (+21)


Example with attached mod.py:

$ ./python -m mod
['__main__',
 '_abc',
 '_codecs',
 '_collections',
 '_collections_abc',
 '_frozen_importlib',
 '_frozen_importlib_external',
 '_functools',
 '_heapq',
 '_imp',
 '_io',
 '_locale',
 '_operator',
 '_signal',
 '_sitebuiltins',
 '_sre',
 '_stat',
 '_thread',
 '_warnings',
 '_weakref',
 '_weakrefset',
 'abc',
 'builtins',
 'codecs',
 'collections',
 'collections.abc',
 'contextlib',
 'copyreg',
 'encodings',
 'encodings.aliases',
 'encodings.ascii',
 'encodings.latin_1',
 'encodings.utf_8',
 'enum',
 'functools',
 'genericpath',
 'heapq',
 'importlib',
 'importlib._bootstrap',
 'importlib._bootstrap_external',
 'importlib.abc',
 'importlib.machinery',
 'importlib.util',
 'io',
 'itertools',
 'keyword',
 'marshal',
 'operator',
 'os',
 'os.path',
 'pkgutil',
 'posix',
 'posixpath',
 're',
 'reprlib',
 'runpy',
 'site',
 'sre_compile',
 'sre_constants',
 'sre_parse',
 'stat',
 'sys',
 'time',
 'types',
 'typing',
 'typing.io',
 'typing.re',
 'warnings',
 'weakref',
 'zipimport']
Total 70

----------
components: Library (Lib)
files: mod.py
messages: 371741
nosy: vstinner
priority: normal
severity: normal
status: open
title: Reduce number of modules imported by runpy
versions: Python 3.10
Added file: https://bugs.python.org/file49240/mod.py

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue41006>
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