Date: Thu, 4 Dec 2014 01:59:01 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Dave Jones <davej@redhat.com>
cc: Linus Torvalds <torvalds@linux-foundation.org>, Chris Mason <clm@fb.com>,
        Mike Galbraith <umgwanakikbuti@gmail.com>,
        Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>,
        =?ISO-8859-15?Q?D=E2niel_Fraga?= <fragabr@gmail.com>,
        Sasha Levin <sasha.levin@oracle.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        John Stultz <john.stultz@linaro.org>
Subject: Re: frequent lockups in 3.18rc4
In-Reply-To: <20141204002044.GA15239@redhat.com>
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On Wed, 3 Dec 2014, Dave Jones wrote:
> On Thu, Dec 04, 2014 at 12:49:29AM +0100, Thomas Gleixner wrote:
> 
>  > > I just got 
>  > > 
>  > > [ 1472.614433] Clocksource tsc unstable (delta = -26373048906 ns)
>  > > 
>  > > without any sign of the pr_err above.
>  > 
>  > Bah. Would have been too simple ....
>  > 
>  > Could you please run Ingos time-warp test on that machine for a while?
>  > 
>  >    http://people.redhat.com/mingo/time-warp-test/time-warp-test.c
>  > 
>  > Please change:
>  > 
>  > - #define TEST_CLOCK 0
>  > + #define TEST_CLOCK 1
> 
> Seems to be 32-bit only, so I built it with -m32. I assume that's ok?

I has some _x86_64 ifdeffery, but I'm too tired to stare at that
now. 32bit should show the issue as well.
 
> Also, should I run it in isolation, with nothing else going on,
> or under load where I see problems ?

isolated is usually the best thing as it has the highest density of
reads.

Thanks,

	tglx
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