From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Discordant results between UnixBench and nBench Date: Wed, 23 Dec 2009 14:59:26 +0200 Message-ID: <4B32142E.4090705@redhat.com> References: <4B31E88B.6020002@redhat.com> <4B31F2FD.4010201@redhat.com> <4B320F93.6080700@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Matthieu Olivier Return-path: Received: from mx1.redhat.com ([209.132.183.28]:24503 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755190AbZLWM72 (ORCPT ); Wed, 23 Dec 2009 07:59:28 -0500 In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On 12/23/2009 02:55 PM, Matthieu Olivier wrote: > > I can only see 4 cores in /proc/cpuinfo. > According the caract page, there is no hyperthreading. > > -> http://ark.intel.com/Product.aspx?id=35130 > > In this case the plateau at 4 guests is perfectly understandable. > I also wonder why the host can still get more CPU ressources over 4 > threads? I guess the purpose of both benchmarks is to overload the > CPU, so why they can't reach the max? > Probably a problem with the benchmark itself. > I suposed that the FPU was able to handle at least 2 operations the > same time, or maybe hyperthreading was included, but I can't check the > first part, and the second isn't true. > > Or maybe current x86 processors can handel very well these old > benchmarks. I can't really say :/ > No, you should see the same plateau as with kvm. The processor can't run two threads at once. -- error compiling committee.c: too many arguments to function