From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Luvalley-2 has been released: running KVM below any operating system Date: Sun, 19 Apr 2009 14:44:34 +0300 Message-ID: <49EB0EA2.6090206@redhat.com> References: <3b0605b30904151853n60075dc9g51a94f94613daca@mail.gmail.com> <706158FABBBA044BAD4FE898A02E4BC232872086@pdsmsx503.ccr.corp.intel.com> <3b0605b30904170154o4e0a559do34690b877c477972@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit Cc: "Zhang, Xiantao" , "kvm@vger.kernel.org" To: Xiaodong Yi Return-path: Received: from mx2.redhat.com ([66.187.237.31]:56621 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756580AbZDSLor (ORCPT ); Sun, 19 Apr 2009 07:44:47 -0400 In-Reply-To: <3b0605b30904170154o4e0a559do34690b877c477972@mail.gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: Xiaodong Yi wrote: > Hi, > > I've tested the guest Linux using UnixBench 5.1.2. The platform is: > * Intel's Core Due CPU with 2 cores, 2GB RAM > * CentOS 5.2 as the dom0 Linux, i.e., the host Linux for KVM > * CentOS 5.2 as the guest Linux, i.e., the Linux running on the > virtual machine provided by Qemu > > The first set of results is for Luvalley, and the second one is for > KVM. As the result, Luvalley's guest Linux is 20% ~ 30% faster than > KVM's guest! It is very surprise to me. I had through Luvalley's guest > should be the same performance as KVM's. > > Yes, it is surprising. > Double-Precision Whetstone 12287.7 MWIPS (10.0 s, 2 samples) > Double-Precision Whetstone 2166.3 MWIPS (10.2 s, 2 samples That's by far the biggest difference. Can you confirm it isn't a typo? If not, then it looks like we have a bug in floating point handling. I don't think this benchmark uses sse. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.