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

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Date:	Wed, 25 Aug 2010 12:41:30 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Robert Richter <robert.richter@....com>
Cc:	Don Zickus <dzickus@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Cyrill Gorcunov <gorcunov@...il.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


* Robert Richter <robert.richter@....com> wrote:

> On 20.08.10 11:25:10, Ingo Molnar wrote:
> 
> > > Ingo Molnar <mingo@...e.hu> 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.
> > 
> > FYI, it does not trigger on an AMD box.
> 
> Ingo,
> 
> do you mean it does not trigger false positives on AMD? [...]

Correct, on AMD boxes i do not get this message during the first 'perf 
top' run:

> > > > 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

Before the two patches i did not get these messages at all, on any of 
the systems.

> You might use the debug patch below for diagnostics.

Thanks, will try that and report back.

	Ingo
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