From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: Questing regarding KVM Guest PMU Date: Mon, 19 Mar 2012 09:07:28 +0200 Message-ID: <20120319070728.GI27306@redhat.com> References: <20120318103020.GA27306@redhat.com> <20120318145045.GD27306@redhat.com> <20120318165120.GF27306@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: shashank rachamalla Return-path: Received: from mx1.redhat.com ([209.132.183.28]:32734 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757312Ab2CSHKb (ORCPT ); Mon, 19 Mar 2012 03:10:31 -0400 Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Mar 19, 2012 at 12:20:30PM +0530, shashank rachamalla wrote: > On Sun, Mar 18, 2012 at 10:21 PM, Gleb Natapov wrote: > > On Sun, Mar 18, 2012 at 09:47:55PM +0530, shashank rachamalla wrote: > >> >> I guess things are working fine with perf. But why not with oprofile ? > >> >> > >> > Looks like it. I never tried oprofile. Will try to reproduce your > >> > problem and see what oprofile is doing. > >> > >> I am using ubuntu 10.04 with 2.6.32-21-generic kernel as guest and > >> oprofile 0.9.6. > >> Also, I have tried to capture kvm-events ( perf patch ) in host while > >> running oprofile and perf in guest. > >> Please see the attachment. I have run the tests in three cases for the > >> around 5 secs. > >> > >> There are more number of MSR reads and writes in case of perf which I > >> think is normal. However, there are very few MSR reads and writes with > >> oprofile. Also, the number of NMI exceptions are too high in case of > >> oprofile. > >> > > Which host kernel are you using? Try latest kvm.git and check if you see > > something unusual in dmesg. > > Currenly running 3.3.0-rc5. will try with the latest source from kvm > git and let you know. > > Thanks, there were some fixes that didn't make it into 3.3. rdpmc instruction emulation fix is one of them. If oprofile uses it this can explain the problem. -- Gleb.