From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Ahern Subject: Re: [PATCH v2 00/11] KVM in-guest performance monitoring Date: Thu, 16 Jun 2011 09:04:12 -0600 Message-ID: <4DFA1B6C.8040309@cisco.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> <4DF8DD87.8040905@redhat.com> <4DF8E328.6070708@cisco.com> <4DFA0AC4.9050702@redhat.com> <4DFA0E56.70301@cisco.com> <4DFA10DA.4030704@cisco.com> <4DFA1148.6070306@redhat.com> <4DFA1407.8020104@cisco.com> <4DFA14F8.2060109@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org, Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo To: Avi Kivity Return-path: Received: from sj-iport-3.cisco.com ([171.71.176.72]:11423 "EHLO sj-iport-3.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754969Ab1FPPEX (ORCPT ); Thu, 16 Jun 2011 11:04:23 -0400 In-Reply-To: <4DFA14F8.2060109@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 06/16/2011 08:36 AM, Avi Kivity wrote: > On 06/16/2011 05:32 PM, David Ahern wrote: >> Seems to be a side effect of running perf-stat in the guest. Running >> just 'openssl speed aes' in both host and guest shows very similar >> numbers (for the first 3 columns). Adding the 'perf stat' to the command >> (ie., perf stat openssl speed aes) causes a significant decline in the >> guest - by a factor of 2. For comparison 'perf stat' in the host has a >> negligible impact. > > That's pretty bad. I'll investigate. > Before I let this go for the day .... Running perf in the host shows arch_local_irq_enable is a lot more prevalent when adding 'perf stat' to the command in the guest. David