[pypy-dev] Unicode encode/decode speed (cont)

[Maciej Fijalkowski]

On Tue, Feb 19, 2013 at 2:09 PM, Eleytherios Stamatogiannakis
<estama at gmail.com> wrote:
> On 18/02/13 21:15, Amaury Forgeot d'Arc wrote:
>>
>> 2013/2/18 Alex Gaynor <alex.gaynor at gmail.com
>> <mailto:alex.gaynor at gmail.com>>
>>
>>
>>     So, iter(file).next() is slow?
>>
>>
>> Yes, but only with "rU" mode.
>> My benchmark with yesterday's build:
>>
>> $ ~/pypy/pypy-c-jit-60005-0f1e91da6cb2-linux64/bin/pypy -m timeit "fp =
>> open('/tmp/large-text-file'); list(fp)"
>> 10 loops, best of 3: 43.5 msec per loop
>> $ ~/pypy/pypy-c-jit-60005-0f1e91da6cb2-linux64/bin/pypy -m timeit "fp =
>> open('/tmp/large-text-file', 'rU'); list(fp)"
>> 10 loops, best of 3: 638 msec per loop
>>
>> 15 times slower...
>>
>
> Yes you are right. We rerun the query without the 'rU' and the result is:
>
> CPython: 328 msec
> PyPy: 443 msec
> PyPy (with 'rU'): 1 min 17 sec
>
>
> So the main culprit of PyPy's slowdown is 'rU' option in open.
>
> Thanks for looking into it.
>
>
> l.
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Is this yet-another-fault-of-streamio?