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Date: Thu, 7 Nov 2002 11:20:05 -0500 (EST)
From: Bill Davidsen <davidsen@tmr.com>
To: John Levon <levon@movementarian.org>
cc: Ingo Molnar <mingo@elte.hu>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: NMI watchdog question.
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On Wed, 6 Nov 2002, John Levon wrote:

> On Wed, Nov 06, 2002 at 11:49:07AM -0800, george anzinger wrote:
> 
> > So the performance counters are only used on UP machines?
> 
> no. nmi_watchdog=1 -> I/O APIC is used iff available and it works
> nmi_watchdog=2 -> local APIC LVTPC set to interrupt in NMI mode when
> perfctr overflows.
> 
> =2 can be used on both UP and SMP, =1 is only available on UP for the
> rare machines that have an I/O APIC on a UP motherboard (I believe there
> are some, but I don't know if the code is set up to do so properly).

By any chance, does this implementation imply that if I boot SMP with
'noapic' the NMI watchdog won't work? It doesn't, but I am not sure I had
it on before I turned off the APIC.

Clearly this would be desirable to work, as noapic is needed on a fairly
large minority of machines.

-- 
bill davidsen <davidsen@tmr.com>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.

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