Antoine Pitrou <pit...@free.fr> added the comment: Ah, sorry, false alarm. "b[:] = b" actually makes a temporary copy of the bytearray when assigning to itself (!).
However, there's still another strange regression: $ ./python -m timeit \ -s "n=300000; f=open('10MB.bin', 'rb', buffering=0); b=bytearray(n)" \ "f.seek(0);f.readinto(b)" -> default branch: 10000 loops, best of 3: 43 usec per loop -> default branch with patch reverted: 10000 loops, best of 3: 27.5 usec per loop FileIO.readinto executes a single read() into the passed buffer. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue11849> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com