From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754803Ab0DNKd6 (ORCPT ); Wed, 14 Apr 2010 06:33:58 -0400 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 ); Wed, 14 Apr 2010 06:33:57 -0400 Message-ID: <4BC59A01.3070802@redhat.com> Date: Wed, 14 Apr 2010 13:33:37 +0300 From: Avi Kivity User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100330 Fedora/3.0.4-1.fc12 Thunderbird/3.0.4 MIME-Version: 1.0 To: Sheng Yang CC: "Zhang, Yanmin" , Ingo Molnar , Peter Zijlstra , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Marcelo Tosatti , oerg Roedel , Jes Sorensen , Gleb Natapov , Zachary Amsden , zhiteng.huang@intel.com, tim.c.chen@intel.com, Arnaldo Carvalho de Melo Subject: Re: [PATCH V3] perf & kvm: Enhance perf to collect KVM guest os statistics from host side 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> In-Reply-To: <201004141827.21877.sheng@linux.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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