Re: [4.9-rc1] Build-time 2x slower

["Jörg Otte" <jrg.otte@gmail.com>]

2016-10-19 22:55 GMT+02:00 Rafael J. Wysocki <rjw@rjwysocki.net>:
> On Wednesday, October 19, 2016 06:59:35 PM Jörg Otte wrote:
>> 2016-10-19 17:29 GMT+02:00 Linus Torvalds <torvalds@linux-foundation.org>:
>> > On Wed, Oct 19, 2016 at 4:07 AM, Jörg Otte <jrg.otte@gmail.com> wrote:
>> >>
>> >> Additional info: I usally use schedutil governor.
>> >> If I switch to performance governor problems go away.
>> >> Maybe a cpufreq problem?
>> >
>> > Oh, I completely misread the original bug report, and then didn't read
>> > your confirmation email right.
>> >
>> > I thought you had a slower build of the different kernels (when
>> > building on the same kernel), and that the _build_ itself had slowed
>> > down for some reason. But you're actually saying that doing the _same_
>> > build actually takes longer when running on 4.9-rc1.
>>
>> Exactly!
>>
>> Btw: ondemand governor is also good.
>>
>> > There are a few small cpufreq changes there in between commit
>> > 29fbff8698fc (that you reported was fine - please tell me I got _that_
>> > right, at least?) and 4.9-rc1.
>>
>> Perfect! That's what I mean.
>>
>> > Adding Rafael to the cc.
>> >
>> > That said, none of them look all that likely to me. It *would* be good
>> > if you could bisect it a bit (perhaps not fully, but a couple of
>> > bisection steps to narrow down what area it is).
>>
>> I try that tomorrow.
>
> Well, please try commit ef98988ba369 (Merge tag 'pm-extra-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm) which is the
> merge introducing the late cpufreq changes.  If the issue is there, please
> try to revert commit 899bb6642f2a (cpufreq: skip invalid entries when searching
> the frequency) which is the only cpufreq one that may matter for the schedutil
> governor (and I have one fix for that commit queued up already).
>

I first tried the merge but git said I'm already uptodate (my tree
is at 1a1891d Merge tag 'for-f2fs-4.9-rc2' of
git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs already)

Then I did the revert of 899bb6642f2a and
that worked fine for me.

Thanks, Jörg