[Python-Dev] file.readinto performance regression in Python 3.2 vs. 2.7? (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Fri Nov 25 11:55:04 CET 2011

On Fri, 25 Nov 2011 08:38:48 +0200 Eli Bendersky <eliben at gmail.com> wrote:

Just to be clear, there were two separate issues raised here. One is the speed regression of readinto() from 2.7 to 3.2, and the other is the relative slowness of justread() in 3.3 Regarding the second, I'm not sure it's an issue because I tried a larger file (100MB and then also 300MB) and the speed of 3.3 is now on par with 3.2 and 2.7 However, the original question remains - on the 100MB file also, although in 2.7 readinto is 35% faster than readandcopy(), on 3.2 it's about the same speed (even a few % slower). That said, I now observe with Python 3.3 the same speed as with 2.7, including the readinto() speedup - so it appears that the readinto() regression has been solved in 3.3? Any clue about where it happened (i.e. which bug/changeset)?

It would probably be http://hg.python.org/cpython/rev/a1d77c6f4ec1/

Regards

Antoine.

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