From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755129Ab2GIPAR (ORCPT ); Mon, 9 Jul 2012 11:00:17 -0400 Received: from merlin.infradead.org ([205.233.59.134]:43119 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752225Ab2GIPAQ convert rfc822-to-8bit (ORCPT ); Mon, 9 Jul 2012 11:00:16 -0400 Message-ID: <1341845999.3462.86.camel@twins> Subject: Re: perf with precise attribute kills all KVM based VMs From: Peter Zijlstra To: Avi Kivity Cc: David Ahern , Gleb Natapov , LKML Date: Mon, 09 Jul 2012 16:59:59 +0200 In-Reply-To: <4FFAEFF1.9000706@redhat.com> References: <4FFAE6D8.5050609@gmail.com> <20120709141904.GC7298@redhat.com> <1341843844.3462.75.camel@twins> <4FFAED16.7050204@redhat.com> <4FFAEF13.7010108@gmail.com> <1341845396.3462.81.camel@twins> <4FFAEFF1.9000706@redhat.com> Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2012-07-09 at 17:51 +0300, Avi Kivity wrote: > On 07/09/2012 05:49 PM, Peter Zijlstra wrote: > > On Mon, 2012-07-09 at 08:47 -0600, David Ahern wrote: > >> > >> I found this testing changes to perf-kvm, but found the problem extends > >> to just perf-record. With perf-record exclude_guest defaults to 1. See > >> tools/perf/util/util.c, event_attr_init(). > > > > You lost me there.. so perf-record defaults to exclude_guest=1 (which > > would make the proposed patch I just send actually possible), but its > > still going *bang* ? > > It's possible that the DS writes overshoot the MSR... or that there's a > bug somewhere. OK, so the first thing to stare at is in what order the MSRs are touched, I think you first need to stop the counter, then clear the PEBS bits, then clear the DS_AREA one.