[Python-Dev] cpython: Issue #22003: When initialized from a bytes object, io.BytesIO() now (original) (raw)

Antoine Pitrou antoine at python.org
Wed Jul 30 15:59:48 CEST 2014

Le 30/07/2014 02:11, Serhiy Storchaka a écrit :

30.07.14 06:59, Serhiy Storchaka написав(ла):

30.07.14 02:45, antoine.pitrou написав(ла):

http://hg.python.org/cpython/rev/79a5fbe2c78f changeset: 91935:79a5fbe2c78f parent: 91933:fbd104359ef8 user: Antoine Pitrou <solipsis at pitrou.net> date: Tue Jul 29 19:41:11 2014 -0400 summary: Issue #22003: When initialized from a bytes object, io.BytesIO() now defers making a copy until it is mutated, improving performance and memory use on some use cases.

Patch by David Wilson. Did you compare this with issue #15381 [1]?

Not really, but David's patch is simple enough and does a good job of accelerating the read-only BytesIO case.

$ ./python -m timeit -s 'import i' 'i.readlines()'

Before patch: 10 loops, best of 3: 46.9 msec per loop After issue22003 patch: 10 loops, best of 3: 36.4 msec per loop After issue15381 patch: 10 loops, best of 3: 27.6 msec per loop

I'm surprised your patch does better here. Any idea why?

Regards

Antoine.

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