Re: More cpufreq breakage

[Borislav Petkov <bp@alien8.de>]

On Sat, Mar 23, 2013 at 08:46:00PM +0530, Viresh Kumar wrote:
> On 23 March 2013 20:04, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> > I think otherwise, Its the cpu online path but this didn't happened for
> > first boot (probably).
> 
> I tried on my 4 cpu laptop and my bad, couldn't reproduce the issue
> reported by both Borislav and Duncan :(
> 
> Hibernation logs (Borislav's bug):
> https://pastebin.linaro.org/2019/
> 
> cpufreq-info after hibernation (same happens with suspend)  (Duncan's bug):
> https://pastebin.linaro.org/2020/

Those pastebin things want a login. Use a free one.

> The main difference between our systems is number of cpu groups that
> share clock line. On setup of both Duncan and Borislav, they had total
> of 8 cpus and four groups 0-1, 2-3, 4-5, 6-7. And thus have four
> policy structures. And i have only one group 0-1-2-3 and thus only one
> policy struct.

So this should give you a clue - you need to repro it on a similar
machine and your laptop is obviously not similar.

> @Borislav: BTW, can you try reproducing your issue again? If that is
> reproducible?

I've seen it only once so far and I've suspended the machine a bunch of
times already. So I don't think it is that easy to reproduce.

> I don't see (logically) how sub_preempt_count() can be called from
> cpufreq_governor_dbs()? As it is mostly called from kernel/sched/ part
> only.

As Rafael said, there's a notifier running which can, AFAICT, disable
preemption on another CPU in parallel, for example.

> If you still get it, try disabling cpufreq completely and see if it is
> gone or not.

Unfortunately this is my desktop machine and I don't want to test stuff
on it because I need it to work. And I've already downgraded to 3.8.3
because of the other cpufreq breakage which kept a subset of the cores
at max freq because acpi-cpufreq wasn't loading on them.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--