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Date: Thu, 7 Dec 2000 19:29:58 +0100
From: Andi Kleen <ak@suse.de>
To: "Maciej W. Rozycki" <macro@ds2.pg.gda.pl>
Cc: Andi Kleen <ak@suse.de>, richardj_moore@uk.ibm.com,
        linux-kernel@vger.kernel.org
Subject: Re: Why is double_fault serviced by a trap gate?
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In-Reply-To: <Pine.GSO.3.96.1001207190920.21086K-100000@delta.ds2.pg.gda.pl>; from macro@ds2.pg.gda.pl on Thu, Dec 07, 2000 at 07:11:57PM +0100
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On Thu, Dec 07, 2000 at 07:11:57PM +0100, Maciej W. Rozycki wrote:
> On Thu, 7 Dec 2000, Andi Kleen wrote:
> 
> > How often does the NMI watchdog handler run ? 
> 
>  HZ times per second.

Interesting. One of my ports references for PCs lists

0044    r/w     PIT  counter 3 (PS/2, EISA)
                used as fail-safe timer. generates an NMI on time out.
                for user generated NMI see at 0462.



I don't know if modern PCs still provide this counter, but if yes it could
be used for a slow NMI watchdog that only runs every 30s or so. 

-Andi
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