From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: What are the rules for hyperthreaded CPUs? Date: Mon, 05 Dec 2011 11:42:01 +0400 Message-ID: <4EDC75C9.9000500@msgid.tls.msk.ru> References: <4EDC1DC7.7030605@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Todd And Margo Chester Return-path: Received: from isrv.corpit.ru ([86.62.121.231]:37597 "EHLO isrv.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751045Ab1LEHmG (ORCPT ); Mon, 5 Dec 2011 02:42:06 -0500 In-Reply-To: <4EDC1DC7.7030605@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: On 05.12.2011 05:26, Todd And Margo Chester wrote: >> Hi All, >> >> My host has an i7-960 processor (4 cores, 8 hypterthreaded cores.) >> /proc/cpuinfo on my host shows 8 processors. >> >> On my Fedora Core 16 guest, /proc/cpuinfo shows 4 processors. >> >> Question: what is the maximum number of processors I can assign to my >> guest? 4 or 8? What are the rules for Hyperthreading? >> >> Many thanks, >> -T > > Figured it out. The max cores is the number of hyperthreaded cores > (eight in my case). The maximum number of guest vCPUs is unlimited - you can assign, say, 100 cores - each vCPU core is just a thread on host, it does not correspond to any physical characteristics of your host. /mjt