linux-kernel - Re: 2.6.18 Nasty Lockup

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Message-Id: <1160175452.6140.45.camel@localhost.localdomain>
Date:	Fri, 06 Oct 2006 15:57:32 -0700
From:	john stultz <johnstul@...ibm.com>
To:	caglar@...dus.org.tr
Cc:	Greg Schafer <gschafer@....com.au>, linux-kernel@...r.kernel.org,
	Andi Kleen <ak@....de>
Subject: Re: 2.6.18 Nasty Lockup

On Fri, 2006-09-29 at 11:49 +0300, S.Çağlar Onur wrote:
> 28 Eyl 2006 Per 14:39 tarihinde, S.Çağlar Onur şunları yazmıştı: 
> > 27 Eyl 2006 Çar 22:14 tarihinde, john stultz şunları yazmıştı:
> > > Ok. Good to hear you have a workaround. Now to sort out why your TSCs
> > > are becoming un-synced. From the dmesg you sent me privately, I noticed
> > > that while you have 4 cpus, the following message only shows up once:
> > >
> > > ACPI: Processor [CPU1] (supports 8 throttling states)
> > >
> > > Does disabling cpufreq change anything?
> >
> > By the way i tried but nothing changes :(
> 
> Is there any other advice available? Is there anything else you want me to 
> try?

Hey S.Çağlar,

	So I just wrote up this test case that will show how skewed the TSCs
are. I'd be interested if you could run it a few times quickly after a
fresh boot, and then again a day or so later.

See the header comment for instructions.

And just a fair warning: this runs w/ SCHED_FIFO, and thus has the
potential to hang your system (while writing it I made a few flubs and
it hung my system). I believe I've got all of the issues fixed (tested
on a few systems), but wanted to give you a fair warning before I
suggest you run this.  :)

thanks
-john

View attachment "tsc-drift.c" of type "text/x-csrc" (3433 bytes)