From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v2 00/11] KVM in-guest performance monitoring Date: Wed, 15 Jun 2011 19:27:51 +0300 Message-ID: <4DF8DD87.8040905@redhat.com> References: <1307972106-2468-1-git-send-email-avi@redhat.com> <4DF66B1A.6060606@cisco.com> <4DF71DA3.2080300@redhat.com> <4DF7972F.3040103@cisco.com> <4DF79941.9050705@siemens.com> <4DF79B6F.10102@cisco.com> <4DF79EFE.1050201@cisco.com> <4DF7A436.8090308@cisco.com> <4DF873FD.6040903@redhat.com> <4DF8A82F.5090900@cisco.com> <4DF8B1F8.6030502@redhat.com> <4DF8D8FE.2080808@cisco.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org, Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo To: David Ahern Return-path: Received: from mx1.redhat.com ([209.132.183.28]:28639 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755056Ab1FOQ2N (ORCPT ); Wed, 15 Jun 2011 12:28:13 -0400 In-Reply-To: <4DF8D8FE.2080808@cisco.com> Sender: kvm-owner@vger.kernel.org List-ID: On 06/15/2011 07:08 PM, David Ahern wrote: > > What does > > dmesg say about Perf? > > [ 0.050995] Performance Events: Nehalem events, core PMU driver. > [ 0.051466] ... version: 1 > [ 0.052998] ... bit width: 40 > [ 0.053999] ... generic registers: 2 > [ 0.054998] ... value mask: 000000ffffffffff > [ 0.055998] ... max period: 000000007fffffff > [ 0.057997] ... fixed-purpose events: 0 > [ 0.058998] ... event mask: 0000000000000003 Well, it's not a Nehalem. Can you tweak the model/family (via -cpu host) so it doesn't match a Nehalem and instead falls on the architectural PMU? Trial-and-error should work to find a good combo. > > > >> Also, the numbers for branches and branch-misses just seem wrong > >> compared to the same command run in the host as well as running > >> perf-stat in the host on the vcpu thread running openssl (with the vcpu > >> pinned to a pcpu). > > > > Could be due to the fact that the counter is running in host mode. Will > > You mean when perf is run in the guest? Yes - it's counting host events (mostly kvm.ko) as well as guest events. > > be fixed once the exclude_host/exclude_guest patch makes it in (and > > gains Intel support). > > > > How does exclude_{host,_guest} help if the guest-side counters are low > -- by orders of magnitude? It's probably the misidentification as Nehalem. -- error compiling committee.c: too many arguments to function