[Python-Dev] Python 3.0.1 (io-in-c)

Paul Moore p.f.moore at gmail.com
Wed Jan 28 13:10:29 CET 2009

2009/1/28 Antoine Pitrou <solipsis at pitrou.net>:
> Paul Moore <p.f.moore <at> gmail.com> writes:
>> It would be helpful to limit this cost as much as possible - maybe
>> that's simply ensuring that the default encoding for open is (in the
>> majority of cases) a highly-optimised one whose costs *don't* dominate
>> in the way you describe
> As I pointed out, utf-8, utf-16 and latin1 decoders have already been optimized
> in py3k. For *pure ASCII* input, utf-8 decoding is blazingly fast (1GB/s here).
> The dataset for iobench isn't pure ASCII though, and that's why it's not as fast.

Ah, thanks. Although you said your data was 95% ASCII, and you're
getting decode speeds of 250MB/s. That's 75% slowdown for 5% of the
data! Surely that's not right???

> People are invited to test their own workloads with the io-c branch and report
> performance figures (and possible bugs). There are so many possibilities that
> the benchmark figures given by a generic tool can only be indicative.

At the moment, I don't have the time to download and build the branch,
and in any case as I only have Visual Studio Express, I don't get the
PGO optimisations, making any tests I do highly suspect.


PS Can anyone comment on why Python defaults to utf-8 on Windows? That
seems like a highly suspect default...

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