From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: Lost of performance over AMD-V with KVM? Date: Tue, 9 Jul 2013 16:33:40 +0300 Message-ID: <20130709133340.GA24941@redhat.com> References: <51DC001B.2010703@usc.es> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: Victor fernandez Return-path: Received: from mx1.redhat.com ([209.132.183.28]:3340 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753656Ab3GINds (ORCPT ); Tue, 9 Jul 2013 09:33:48 -0400 Content-Disposition: inline In-Reply-To: <51DC001B.2010703@usc.es> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Jul 09, 2013 at 02:20:43PM +0200, Victor fernandez wrote: > Hi EveryBody! > > recently, we have tested some specific High Energy Physics benchmarks that > was running over S.L.6 and we observed that the performance over AMD > machines was really bad, about 30-40% lost. We were investigating > and we conclude that the problem was with some cpu flags. These cpu > flags are important for running our application because it is optimazed > for running with them. So, we tuning our KVM with the name of flags > parameters and with "-cpu host" parameter too, but > we observed that the flags that we needed, they weren't included when > we started the S.L.6 instance. We try to solve it, but when we conclude > that the specific flags weren't included in the code of the last > versions of KVM > and LibVirt(capabilities). Do you know something about this problem or > you are aware of this? > What flags are missing? -- Gleb.