linux-kernel - Re: [PATCH -v3] perf, x86: try to handle unknown nmis with running perfctrs

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Date:	Sat, 21 Aug 2010 00:45:58 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Don Zickus <dzickus@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Robert Richter <robert.richter@....com>,
	Lin Ming <ming.m.lin@...el.com>,
	"fweisbec@...il.com" <fweisbec@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Huang, Ying" <ying.huang@...el.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH -v3] perf, x86: try to handle unknown nmis with running
	perfctrs

On Fri, Aug 20, 2010 at 04:17:03PM +0200, Ingo Molnar wrote:
> 
> it's not working so well, i'm getting:
> 
>  Uhhuh. NMI received for unknown reason 00 on CPU 9.
>  Do you have a strange power saving mode enabled?
>  Dazed and confused, but trying to continue
> 
> on a nehalem box, after a perf top and perf stat run.
> 
> Thanks,
> 
> 	Ingo
> 

Might not this be the case of AAN93 erratum, which says the following

 | The processor can be configured to issue a PMI (performance monitor interrupt)
 | upon overflow of the IA32_FIXED_CTR0 MSR (309H). A single PMI should be observed on
 | overflow of IA32_FIXED_CTR0, however multiple PMIs are observed when this
 | erratum occurs.

Just a thought.

	-- Cyrill
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