linux-kernel - Re: [PATCH -v2] perf, x86: try to handle unknown nmis with running perfctrs

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Message-ID: <20100817152308.GB5879@lenovo>
Date:	Tue, 17 Aug 2010 19:23:08 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Robert Richter <robert.richter@....com>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Don Zickus <dzickus@...hat.com>,
	Lin Ming <ming.m.lin@...el.com>, Ingo Molnar <mingo@...e.hu>,
	"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 -v2] perf, x86: try to handle unknown nmis with running
	perfctrs

On Tue, Aug 17, 2010 at 12:55:25AM +0200, Robert Richter wrote:
> On 16.08.10 15:06:59, Cyrill Gorcunov wrote:
> > I suspect Peter was supposed to be in To: field ;)
> 
> It was the attempt to answer 2 mails with one. :)
> 

ah, I see ;)

> > Robert, I think we still may miss unknown irq, consider the case when
> > unknown nmi is latched while you handle nmi from perf and what is
> > more interesting several counters may be overflowed. So you set
> > delta small enough and second (unknown nmi) will be in range and
> > treated as being perf back-to-back, or I miss something from patch?
> 
> Yes, that's true, but before you have to enable your Infinite
> Improbability Drive.
> 

not at all, it's absolutely legit to happen ;)

> -Robert
> 
> -- 
> Advanced Micro Devices, Inc.
> Operating System Research Center
> 
	-- Cyrill
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