From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937607Ab0CPJsY (ORCPT ); Tue, 16 Mar 2010 05:48:24 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:38325 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932488Ab0CPJsX (ORCPT ); Tue, 16 Mar 2010 05:48:23 -0400 Date: Tue, 16 Mar 2010 10:47:59 +0100 From: Ingo Molnar To: "Zhang, Yanmin" Cc: Avi Kivity , Peter Zijlstra , Sheng Yang , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Marcelo Tosatti , oerg Roedel , Jes Sorensen , Gleb Natapov , Zachary Amsden , zhiteng.huang@intel.com Subject: Re: [PATCH] Enhance perf to collect KVM guest os statistics from host side Message-ID: <20100316094758.GH7961@elte.hu> References: <1268717232.2813.36.camel@localhost> <4B9F19F7.6000309@redhat.com> <1268725724.2813.48.camel@localhost> <1268731733.2813.54.camel@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1268731733.2813.54.camel@localhost> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Zhang, Yanmin wrote: > On Tue, 2010-03-16 at 15:48 +0800, Zhang, Yanmin wrote: > > On Tue, 2010-03-16 at 07:41 +0200, Avi Kivity wrote: > > > On 03/16/2010 07:27 AM, Zhang, Yanmin wrote: > > > > From: Zhang, Yanmin > > > > > > > > Based on the discussion in KVM community, I worked out the patch to support > > > > perf to collect guest os statistics from host side. This patch is implemented > > > > with Ingo, Peter and some other guys' kind help. Yang Sheng pointed out a > > > > critical bug and provided good suggestions with other guys. I really appreciate > > > > their kind help. > > > > > > > > The patch adds new subcommand kvm to perf. > > > > > > > > perf kvm top > > > > perf kvm record > > > > perf kvm report > > > > perf kvm diff > > > > > > > > The new perf could profile guest os kernel except guest os user space, but it > > > > could summarize guest os user space utilization per guest os. > > > > > > > > Below are some examples. > > > > 1) perf kvm top > > > > [root@lkp-ne01 norm]# perf kvm --host --guest --guestkallsyms=/home/ymzhang/guest/kallsyms > > > > --guestmodules=/home/ymzhang/guest/modules top > > > > > > > > > > > > > Thanks for your kind comments. > > > > > Excellent, support for guest kernel != host kernel is critical (I can't > > > remember the last time I ran same kernels). > > > > > > How would we support multiple guests with different kernels? > > With the patch, 'perf kvm report --sort pid" could show > > summary statistics for all guest os instances. Then, use > > parameter --pid of 'perf kvm record' to collect single problematic instance data. > Sorry. I found currently --pid isn't process but a thread (main thread). > > Ingo, > > Is it possible to support a new parameter or extend --inherit, so 'perf > record' and 'perf top' could collect data on all threads of a process when > the process is running? > > If not, I need add a new ugly parameter which is similar to --pid to filter > out process data in userspace. Yeah. For maximum utility i'd suggest to extend --pid to include this, and introduce --tid for the previous, limited-to-a-single-task functionality. Most users would expect --pid to work like a 'late attach' - i.e. to work like strace -f or like a gdb attach. Ingo