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Date: Sat, 8 Dec 2007 20:42:11 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Parag Warudkar <parag.warudkar@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
       "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
       LKML <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: soft lockup - CPU#1 stuck for 15s! [swapper:0]
Message-ID: <20071208194211.GA579@elte.hu>
References: <82e4877d0712071453h38795e36of26324a4b123fa6c@mail.gmail.com> <924EFEDD5F540B4284297C4DC59F3DEE38C3C2@orsmsx423.amr.corp.intel.com> <alpine.LFD.0.99999.0712080821220.3070@localhost.localdomain> <82e4877d0712080710g205ba93ag12ee204b15d70fdb@mail.gmail.com> <82e4877d0712080736v12c1e31at9149655ae000fe50@mail.gmail.com> <20071208154755.GA5255@elte.hu> <82e4877d0712080800j6572734ek78a76cf7bb17a7e0@mail.gmail.com> <20071208191330.GA21186@elte.hu> <82e4877d0712081133y49fec9bfyee30a3010b37c435@mail.gmail.com>
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* Parag Warudkar <parag.warudkar@gmail.com> wrote:

> Even on 100% idle I get variations that are approx in the same range 
> when not idle. Clocksource is hpet if that matters.  Next I think I 
> will disable CPU_IDLE, Tickless

also try the hpet=disable boot option.

> My ssh connection just died - another lockup in dmesg -
> 
> BUG: soft lockup - CPU#1 stuck for 14s! [sshd:509]

this would suggest that the softlockup watchdog is correct and indeed 
there was some lockup of sorts?

> $> while :; do time usleep 1111111; done
> real    0m1.112s
> real    0m1.385s
> real    0m1.112s
> real    0m1.112s
> real    0m1.279s

this, if done on an idle system, looks anomalous to me. Does 
hpet=disable help?

	Ingo