STINNER Victor added the comment: And now something completly differenet: fast_bottom-up.patch, fast bottom-up, but "slow" top-down.
In bottom-up mode (topdown=False), use entry.path and entry.is_symlink() => optimization compared to Python 3.4 (avoid one call to os.stat()). In top-down mode (topdown=True, default), use os.path.join() and os.path.islink() => no change compared to Python 3.4 on this part. More globally, os.walk() should still be much faster in Python 3.5 than in Python 3.5 thanks to entry.is_dir() which avoids a call to os.path.isdir() (and so os.stat()). Correctness matters more than performances! > 2. Accept and document behavior change. This will break someone's code. :-( > 3. Left os.walk as was (or only partially optimized as in 1), and add a new > function with new behavior. > 4. Add new boolean parameter that control behavior to os.walk(). Sorry but all these options sucks :-p > 5. Try to detect when dir list or filesystem were changed. Victor's patch > does the first. For the second we can check if top directory inode and mtime > were changed. But I afraid this wouldn't decrease a number of system calls. By experience, it's very hard to write portable code. Even if we find a way to detect FS change on some platforms, it will not work on some other platforms. ---------- Added file: http://bugs.python.org/file38452/fast_bottom-up.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue23605> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
