[Speed] Latest enhancements of perf 0.8.1 and performance 0.3.1

[Armin Rigo]

Hi Victor,

On 2 November 2016 at 16:53, Victor Stinner <victor.stinner at gmail.com> wrote:
> 2016-11-02 15:20 GMT+01:00 Armin Rigo <armin.rigo at gmail.com>:
>> Is that really the kind of examples you want to put forward?
>
> I am not a big fan of timeit, but we must use it sometimes to
> micro-optimizations in CPython to check if an optimize really makes
> CPython faster or not. I am only trying to enhance timeit.
> Understanding results require to understand how the statements are
> executed.

Don't get me wrong, I understand the point of the following usage of timeit:

    python2 -m perf timeit '[1,2]*1000' --duplicate=1000

What I'm criticizing here is this instead:

    python2 -m perf timeit '[1,2]*1000' --duplicate=1000 --compare-to=pypy

because you're very unlikely to get any relevant information from such
a comparison.  I stand by my original remark: I would say it should be
an error or at least a big fat warning to use --duplicate and PyPy in
the same invocation.  This is as opposed to silently ignoring
--duplicate for PyPy, which is just adding more confusion imho.


A bientôt,

Armin.