From mboxrd@z Thu Jan 1 00:00:00 1970 From: Masami Hiramatsu Subject: Re: [PATCH] Enhance perf to collect KVM guest os statistics from host side Date: Tue, 16 Mar 2010 19:01:57 -0400 Message-ID: <4BA00DE5.80604@redhat.com> References: <4B9F19F7.6000309@redhat.com> <20100316072449.GB11881@elte.hu> <4B9F4D74.4090403@redhat.com> <20100316095336.GI7961@elte.hu> <4B9F59DE.1060008@redhat.com> <20100316102052.GC10069@elte.hu> <4B9F603B.4080004@redhat.com> <20100316105021.GA14344@elte.hu> <4B9F671D.5060001@redhat.com> <20100316112500.GA5337@elte.hu> <20100316223040.GH13108@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Ingo Molnar , Avi Kivity , "Zhang, Yanmin" , Peter Zijlstra , Sheng Yang , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Marcelo Tosatti , Jes Sorensen , Gleb Natapov , Zachary Amsden , ziteng.huang@intel.com, sungho.kim.zd@hitachi.com To: oerg Roedel Return-path: Received: from mx1.redhat.com ([209.132.183.28]:59321 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752175Ab0CPXC2 (ORCPT ); Tue, 16 Mar 2010 19:02:28 -0400 In-Reply-To: <20100316223040.GH13108@8bytes.org> Sender: kvm-owner@vger.kernel.org List-ID: oerg Roedel wrote: > On Tue, Mar 16, 2010 at 12:25:00PM +0100, Ingo Molnar wrote: >> Hm, that sounds rather messy if we want to use it to basically expose kernel >> functionality in a guest/host unified way. Is the qemu process discoverable in >> some secure way? Can we trust it? Is there some proper tooling available to do >> it, or do we have to push it through 2-3 packages to get such a useful feature >> done? > > Since we want to implement a pmu usable for the guest anyway why we > don't just use a guests perf to get all information we want? If we get a > pmu-nmi from the guest we just re-inject it to the guest and perf in the > guest gives us all information we wand including kernel and userspace > symbols, stack traces, and so on. I guess this aims to get information from old environments running on kvm for life extension :) > In the previous thread we discussed about a direct trace channel between > guest and host kernel (which can be used for ftrace events for example). > This channel could be used to transport this information to the host > kernel. Interesting! I know the people who are trying to do that with systemtap. See, http://vesper.sourceforge.net/ > > The only additional feature needed is a way for the host to start a perf > instance in the guest. # ssh localguest perf record --host-chanel ... ? B-) Thank you, > > Opinions? > > > Joerg > > -- > 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/ -- Masami Hiramatsu e-mail: mhiramat@redhat.com