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

[Antoine Pitrou]

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.