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: Tue, 16 Mar 2010 15:37:21 +0200 Message-ID: <4B9F8991.3030700@redhat.com> References: <20100316102052.GC10069@elte.hu> <4B9F603B.4080004@redhat.com> <20100316105021.GA14344@elte.hu> <4B9F671D.5060001@redhat.com> <20100316112500.GA5337@elte.hu> <4B9F77E7.2060101@redhat.com> <20100316122903.GA8831@elte.hu> <4B9F7C6A.3070207@redhat.com> <20100316130840.GA24808@elte.hu> <4B9F84C0.70706@redhat.com> <20100316133114.GB575@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "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: <20100316133114.GB575@elte.hu> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 03/16/2010 03:31 PM, Ingo Molnar wrote: > >> You can do that through libvirt, but that only works for guests started >> through libvirt. libvirt provides command-line tools to list and manage >> guests (for example autostarting them on startup), and tools built on top of >> libvirt can manage guests graphically. >> >> Looks like we have a layer inversion here. Maybe we need a plugin system - >> libvirt drops a .so into perf that teaches it how to list guests and get >> their symbols. >> > Is libvirt used to start up all KVM guests? If not, if it's only used on some > distros while other distros have other solutions then there's apparently no > good way to get to such information, and the kernel bits of KVM do not provide > it. > Developers tend to start qemu from the command line, but the majority of users and all distros I know of use libvirt. Some users cobble up their own scripts. > To the user (and to me) this looks like a KVM bug / missing feature. (and the > user doesnt care where the blame is) If that is true then apparently the > current KVM design has no technically actionable solution for certain > categories of features! > A plugin system allows anyone who is interested to provide the information; they just need to write a plugin for their management tool. Since we can't prevent people from writing management tools, I don't see what else we can do. -- error compiling committee.c: too many arguments to function