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

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Message-ID: <20100812143133.GA5719@lenovo>
Date:	Thu, 12 Aug 2010 18:31:33 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Robert Richter <robert.richter@....com>
Cc:	Don Zickus <dzickus@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	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] perf, x86: try to handle unknown nmis with running
	perfctrs

On Thu, Aug 12, 2010 at 03:24:19PM +0200, Robert Richter wrote:
> On 10.08.10 15:24:28, Cyrill Gorcunov wrote:
> > On Tue, Aug 10, 2010 at 09:05:41PM +0200, Robert Richter wrote:
> > > On 10.08.10 13:24:51, Cyrill Gorcunov wrote:
> > > 
> > > > It gets masked on NMI arrival, at least for some models (Core Duo, P4,
> > > > P6 M and I suspect more theh that, that was the reason oprofile has
> > > > it, also there is a note in SDM V3a page 643).
> > > 
> > > Yes, that's right, I never noticed that. Maybe it is better to
> > > implement the apic write it in model specific code then.
> > > 
> > 
> > Perhaps we can make it simplier I think, ie like it was before -- we just
> > move it under your new DIE_NMIUNKNOWN, in separate patch of course. Though
> > I'm fine with either way.
> 
> I do not understand why you want to put this in the 'unknown'
> path. Isn't it necessary to unmask the vector with every call of the
> nmi handler?
> 
> -Robert
> 

Heh, it's simple - I'm screwed. Robert you're right, of course it should NOT
be under every 'unknown' nmi. I thought about small optimization here, but
I think all this should be done only _after_ your patch is merged.

Sorry for confuse ;)
 
	-- Cyrill
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