From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] Enhance perf to collect KVM guest os statistics from host side Date: Wed, 17 Mar 2010 10:20:27 +0200 Message-ID: <4BA090CB.5020906@redhat.com> References: <20100316133114.GB575@elte.hu> <20100316155221.GA19699@elte.hu> <4B9FC11A.1070507@linux.vnet.ibm.com> <20100316175243.GC23859@elte.hu> <4B9FC8B2.6070404@linux.vnet.ibm.com> <20100316182809.GA26602@elte.hu> <4BA00E6A.7080903@linux.vnet.ibm.com> <20100317004136.GC17472@redhat.com> <4BA05285.3070903@redhat.com> <20100317081641.GE16374@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "Frank Ch. Eigler" , Anthony Liguori , "Zhang, Yanmin" , Peter Zijlstra , Sheng Yang , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Marcelo Tosatti , oerg Roedel , Jes Sorensen , Gleb Natapov , Zachary Amsden , ziteng.huang@intel.com To: Ingo Molnar Return-path: In-Reply-To: <20100317081641.GE16374@elte.hu> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 03/17/2010 10:16 AM, Ingo Molnar wrote: > * Avi Kivity wrote: > > >> Monitoring guests from the host is useful for kvm developers, but less so >> for users. >> > Guest space profiling is easy, and 'perf kvm' is not about that. (plain 'perf' > will work if a proper paravirt channel is opened to the host) > > I think you might have misunderstood the purpose and role of the 'perf kvm' > patch here? 'perf kvm' is aimed at KVM developers: it is them who improve KVM > code, not guest kernel users. > Of course I understood it. My point was that 'perf kvm' serves a tiny minority of users. That doesn't mean it isn't useful, just that it doesn't satisfy all needs by itself. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.