Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759099Ab0FVJ2r (ORCPT ); Tue, 22 Jun 2010 05:28:47 -0400 Received: from mga09.intel.com ([134.134.136.24]:36546 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751897Ab0FVJ2p (ORCPT ); Tue, 22 Jun 2010 05:28:45 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.53,459,1272870000"; d="scan'208";a="529088871" Subject: Re: [PATCH V2 1/5] ara virt interface of perf to support kvm guest os statistics collection in guest os From: "Zhang, Yanmin" To: Jes Sorensen Cc: Peter Zijlstra , Avi Kivity , LKML , kvm@vger.kernel.org, Ingo Molnar , Fr??d??ric Weisbecker , Arnaldo Carvalho de Melo , Cyrill Gorcunov , Lin Ming , Sheng Yang , Marcelo Tosatti , oerg Roedel , Gleb Natapov , Zachary Amsden , zhiteng.huang@intel.com, tim.c.chen@intel.com In-Reply-To: <4C206D8B.4080105@redhat.com> References: <1277112680.2096.509.camel@ymzhang.sh.intel.com> <4C1F50D0.70205@redhat.com> <1277171344.2096.567.camel@ymzhang.sh.intel.com> <4C2062D8.20609@redhat.com> <1277192873.2096.690.camel@ymzhang.sh.intel.com> <1277193305.1875.537.camel@laptop> <4C206D8B.4080105@redhat.com> Content-Type: text/plain; charset="ISO-8859-1" Date: Tue, 22 Jun 2010 17:29:03 +0800 Message-Id: <1277198943.2096.724.camel@ymzhang.sh.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.28.0 (2.28.0-2.fc12) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 993 Lines: 24 On Tue, 2010-06-22 at 10:00 +0200, Jes Sorensen wrote: > On 06/22/10 09:55, Peter Zijlstra wrote: > > On Tue, 2010-06-22 at 15:47 +0800, Zhang, Yanmin wrote: > >> Besides the para virt perf interface, I'm also considering the direct exposition > >> of PMU hardware to guest os. > > > > NAK NAK NAK NAK, we've been over that, its not going to happen, full > > stop! > > > > Use MSR read/write traps and host perf to emulate the hardware. In some > > cases we could allow the reads without trap but that's a later > > optimization. > > I believe whats meant here is a PMU compatible interface which is > partially emulated. Not a handover of the PMU. Right. We need capture all write to PMU MSR and allows guest os to read MSR directly. Yanmin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/