On 14.04.2016 10:39, Alecsandru Patrascu wrote:
> 
> @Stefan and @Marc, you say that people don't want to wait for PGO to build when running ./configure && make, but why? Even though many developers use it, this mode is not intended for development, it is production level and should be run once (or at leas a limited number or times), when the developers are sure that everything is fine in the debug mode. As Victor previously said, we should have all the *good* stuff (PGO, LTO, etc) enabled by default, regardless the time needed to do it.

You need to compile Python a lot during Python development and
here the compile speed matters, the performance of the resulting
binary is secondary (as long as it is consistent).

For production, it's easily possible to add those options to configure,
plus it's not 100% clear whether all optimizations really do create
correct code. We've had lots of issues with optimization errors in
compilers in the past and have generally been rather conservative with
the default optimization settings. It's better to have a stable running
Python, than a Python that is fast at failing or creating wrong
results ;-)

I think having these extra options readily accessible and
working is great, and people who know what they are doing can
then use them for the benefit of getting an even faster Python.

Distributors will know what they are doing, so many Python
users will still be able to benefit from them.