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

[Sedat Dilek]

On Thu, Oct 20, 2016 at 9:57 AM, JÃrg Otte <jrg.otte@xxxxxxxxx> wrote:
> 2016-10-19 22:55 GMT+02:00 Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>:
>> On Wednesday, October 19, 2016 06:59:35 PM JÃrg Otte wrote:
>>> 2016-10-19 17:29 GMT+02:00 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>:
>>> > On Wed, Oct 19, 2016 at 4:07 AM, JÃrg Otte <jrg.otte@xxxxxxxxx> 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)
>

I guess Rafael meant try his latest linux-pm Git tree with branch and
look if the problem still exists.

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

Thanks for the feedback!
Hope I can try the revert and in a 2nd run the possible fix pending in
Rafael's linux-pm.git#linux-next.

- Sedat -

[1] https://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git/patch/?id=f7a7a80ae30521b65a6dfc98df45d3ec9e238d73