On 13 Feb 2013 07:08, "Maciej Fijalkowski" <fijall@gmail.com> wrote:
> Hi
> We recently encountered a performance issue in stdlib for pypy. It
> turned out that someone commited a performance "fix" that uses += for
> strings instead of "".join() that was there before.
> Now this hurts pypy (we can mitigate it to some degree though) and
> possible Jython and IronPython too.
> How people feel about generally not having += on long strings in
> stdlib (since the refcount = 1 thing is a hack)?
> What about other performance improvements in stdlib that are
> problematic for pypy or others?
> Personally I would like cleaner code in stdlib vs speeding up CPython.

For the specific case of "Don't rely on the fragile refcounting hack in CPython's string concatenation" I strongly agree. However, as a general principle, I can't agree until speed.python.org is a going concern and we can get a reasonable overview of any resulting performance implications.


> Typically that also helps pypy so I'm not unbiased.
> Cheers,
> fijal
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