[Python-Dev] FAT Python (lack of) performance

[Andrew Barnert]

On Jan 25, 2016, at 18:21, INADA Naoki <songofacandy at gmail.com> wrote:
> 
> I'm very interested in it.
> 
> Ruby 2.2 and PHP 7 are faster than Python 2.
> Python 3 is slower than Python 2.

Says who?

That was certainly true in the 3.2 days, but nowadays, most things that differ seem to be faster in 3.x. Maybe it's just the kinds of programs I write, but speedup in decoding UTF-8 that's usually ASCII (and then processing the decoded unicode when it's usually 1/4th the size), faster listcomps, and faster datetime seem to matter more than slower logging or slower imports. And that's just when running the same code; when you actually use new features, yield from is much faster than looping over yield; scandir blows away listdir; asyncio blows away asyncore or threading even harder; etc.

Maybe if you do different things, you have a different experience. But if you have a specific problem, you'd do a lot better to file specific bugs for that problem than to just hope that everything magically gets so much faster that your bottleneck no longer matters.

> Performance is a attractive feature.  Python 3 lacks it.

When performance matters, people don't use Python 2, Ruby, or PHP, any more than they use Python 3. Or, rather, they use _any_ of those languages for the 95% of their code that doesn't matter, and C (often through existing libraries like NumPy--and try to find a good equivalent of that for Ruby or PHP) for the 5% that does.