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

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 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.

Paul.

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

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