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From: Gabriele Mazzotta <gabriele.mzt@gmail.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: juri.lelli@arm.com, mingo@redhat.com, peterz@infradead.org,
        linux-kernel@vger.kernel.org, len.brown@intel.com,
        andrey.semin@intel.com
Subject: Re: Regression: turbostat stops working after suspend/resume cycle
Date: Mon, 18 May 2015 09:12:29 +0200
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On Monday 18 May 2015 08:45:52 Ingo Molnar wrote:
> 
> * Gabriele Mazzotta <gabriele.mzt@gmail.com> wrote:
> 
> > Hi,
> > 
> > I've recently noticed that if I suspend and resume my laptop, I can no
> > longer execute turbostat. This is what I get when I try to start it:
> > # turbostat
> > Could not migrate to CPU 1
> > turbostat: re-initialized with num_cpus 4
> > Could not migrate to CPU 1
> > 
> > Since everything works as expected with v4.0, I ran a bisection and
> > found that commit 3c18d447b3b36a8d ("sched/core: Check for available
> > DL bandwidth in cpuset_cpu_inactive()") is the cause of the regression.
> > 
> > I don't know if there's something else affected by that change, but
> > I can consistently reproduce the bug with turbostat.
> > 
> > I can provide more info if needed.
> 
> Does this commit:
> 
>   533445c6e533 sched/core: Fix regression in cpuset_cpu_inactive() for suspend
> 
> which is already in Linus's tree, and which should be part of -rc4, 
> fix it? Also attached below.

Yes, this fixes the problem, thanks. Sorry for not noticing it.

Gabriele