From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH V3] perf & kvm: Enhance perf to collect KVM guest os statistics
 from host side
Date: Wed, 14 Apr 2010 13:33:37 +0300
Message-ID: <4BC59A01.3070802@redhat.com>
References: <1902387910.2078.435.camel@ymzhang.sh.intel.com> <201004141814.19330.sheng@linux.intel.com> <4BC596C5.7020507@redhat.com> <201004141827.21877.sheng@linux.intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>,
	Ingo Molnar <mingo@elte.hu>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Marcelo Tosatti <mtosatti@redhat.com>,
	oerg Roedel <joro@8bytes.org>,
	Jes Sorensen <Jes.Sorensen@redhat.com>,
	Gleb Natapov <gleb@redhat.com>,
	Zachary Amsden <zamsden@redhat.com>, zhiteng.huang@intel.com,
	tim.c.chen@intel.com, Arnaldo Carvalho de Melo <acme@infradead.org>
To: Sheng Yang <sheng@linux.intel.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from mx1.redhat.com ([209.132.183.28]:50213 "EHLO mx1.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1754362Ab0DNKd5 (ORCPT <rfc822;kvm@vger.kernel.org>);
	Wed, 14 Apr 2010 06:33:57 -0400
In-Reply-To: <201004141827.21877.sheng@linux.intel.com>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

On 04/14/2010 01:27 PM, Sheng Yang wrote:
>
>> Yes, interesting to see what the latency is.  If it's reasonably short
>> (and I expect it will be so), we can do the busy wait solution.
>>
>> If we have an NMI counter somewhere, we can simply wait until it changes.
>>      
>
> Good idea. Of course we have one(at least on x86). There is
> irq_stat.irq__nmi_count for per cpu. :)
>    

Okay, but kvm doesn't want to know about it.  How about a new arch 
function, invoke_nmi_sync(), that will trigger the NMI and wait for it?

-- 
error compiling committee.c: too many arguments to function