Serhiy Storchaka added the comment: Seems not all such easy. Looking in sys.module is not enough, we should check __spec__._initializing.
Following patch moves optimizations to PyImport_ImportModuleLevelObject (C implementation of standard __import__). Main optimizations: 1. PyImport_ImportModuleLevelObject is called directly if builtins.__import__ is standard __import__. 2. Import lock is not acquired for looking up in sys.modules and other operations. Some of these operations are atomic in C (guarded by GIL), others are used only for optimization and race condition can cause only insignificant slow down. 3. Avoided creating empty dict for globals, looking up __package__ and __spec__ if they are not needed. 4. Saving standard __import__ in interpreter state. Microbenchmarking results: $ ./python -m timeit 'import os' Unpatched: 1000000 loops, best of 3: 0.845 usec per loop Patched: 1000000 loops, best of 3: 0.338 usec per loop $ ./python -m timeit 'import os.path' Unpatched: 100000 loops, best of 3: 2.07 usec per loop Patched: 1000000 loops, best of 3: 0.884 usec per loop $ ./python -m timeit 'from os import path' Unpatched: 100000 loops, best of 3: 3.7 usec per loop Patched: 100000 loops, best of 3: 2.77 usec per loop ---------- Added file: http://bugs.python.org/file43869/faster_import_6.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue22557> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
