Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758284AbbDWU2f (ORCPT ); Thu, 23 Apr 2015 16:28:35 -0400 Received: from terminus.zytor.com ([198.137.202.10]:56316 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754254AbbDWU2d (ORCPT ); Thu, 23 Apr 2015 16:28:33 -0400 Message-ID: <553955D9.3030600@zytor.com> Date: Thu, 23 Apr 2015 13:28:09 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Dave Hansen , Liang Li , kvm@vger.kernel.org, linux-kernel@vger.kernel.org CC: gleb@kernel.org, pbonzini@redhat.com, mtosatt@redhat.com, tglx@linutronix.de, mingo@redhat.com, x86@kernel.org, joro@8bytes.org, yang.z.zhang@intel.com, Xudong Hao Subject: Re: [v6] kvm/fpu: Enable fully eager restore kvm FPU References: <1429823583-3226-1-git-send-email-liang.z.li@intel.com> <55390F9A.2070808@intel.com> In-Reply-To: <55390F9A.2070808@intel.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 666 Lines: 19 On 04/23/2015 08:28 AM, Dave Hansen wrote: > On 04/23/2015 02:13 PM, Liang Li wrote: >> When compiling kernel on westmere, the performance of eager FPU >> is about 0.4% faster than lazy FPU. > > Do you have an theory why this is? What does the regression come from? > This is interesting since previous measurements on KVM have had the exact opposite results. I think we need to understand this a lot more. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/