[Python-Dev] file.readinto performance regression in Python 3.2 vs. 2.7?

Amaury Forgeot d'Arc amauryfa at gmail.com
Fri Nov 25 16:07:59 CET 2011


2011/11/25 Paul Moore <p.f.moore at gmail.com>

> The optimisation mentioned was an attempt (by mutating an existing
> string when the runtime determined that it was safe to do so) to hide
> the consequences of this fact from end-users who didn't fully
> understand the issues. It was relatively effective, but like any such
> case (floating point is another common example) it did some level of
> harm at the same time as it helped (by obscuring the issue further).
>
> It would be nice to have the optimisation back if it's easy enough to
> do so, for quick-and-dirty code, but it is not a good idea to rely on
> it (and it's especially unwise to base benchmarks on it working :-))
>

Note that this string optimization hack is still present in Python 3,
but it now acts on *unicode* strings, not bytes.

-- 
Amaury Forgeot d'Arc
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