[Python-Dev] Help requested with Python 2.7 performance regression

[INADA Naoki]

On Thu, Mar 2, 2017 at 4:07 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> On Wed, 1 Mar 2017 19:58:14 +0100
> Matthias Klose <doko at ubuntu.com> wrote:
>> On 01.03.2017 18:51, Antoine Pitrou wrote:
>> > As for the high level: what if the training set used for PGO in Xenial
>> > has become skewed or inadequate?
>>
>> running the testsuite
>
> I did some tests a year or two ago, and running the whole test suite is
> not a good idea, as coverage varies wildly from one functionality to the
> other, so PGO will not infer the right information from it.  You don't
> get very good benchmark results from it.
>
> (for example, decimal has an extensive test suite which might lead PGO
> to believe that code paths exercised by the decimal module are the
> hottest ones)
>
> Regards
>
> Antoine.
>

FYI, there are "profile-opt" make target.  It uses subset of regrtest.
https://github.com/python/cpython/blob/2.7/Makefile.pre.in#L211-L214

Does Ubuntu (and Debian) use it?