From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Chmielewski Subject: Houston, we have May 15, 1953 (says guest when host uses cpufreq, and dies) Date: Wed, 18 Feb 2009 15:51:22 +0100 Message-ID: <499C206A.5050109@wpkg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from mx03.syneticon.net ([78.111.66.105]:48122 "EHLO mx03.syneticon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751917AbZBROvU (ORCPT ); Wed, 18 Feb 2009 09:51:20 -0500 Received: from localhost (filter1.syneticon.net [192.168.113.83]) by mx03.syneticon.net (Postfix) with ESMTP id 472A835DF5 for ; Wed, 18 Feb 2009 15:54:13 +0100 (CET) Received: from mx03.syneticon.net ([192.168.113.84]) by localhost (mx03.syneticon.net [192.168.113.83]) (amavisd-new, port 10025) with ESMTP id 4LfZsksTf0Ln for ; Wed, 18 Feb 2009 15:51:14 +0100 (CET) Received: from [192.168.10.145] (koln-4db419c9.pool.einsundeins.de [77.180.25.201]) by mx03.syneticon.net (Postfix) with ESMTPSA for ; Wed, 18 Feb 2009 15:54:09 +0100 (CET) Sender: kvm-owner@vger.kernel.org List-ID: Is using cpufreq (i.e. with ondemand governor) on KVM host safe for guests? I enabled cpufreq on the host, it scaled down the host CPU (Dual-Core AMD Opteron(tm) Processor 2212) to 1 GHz from 2 GHz. Guest (using 1 CPU) was still showing that it has a 2 GHz CPU in /proc/cpuinfo (I guess this value is read only once, when booting). After about 2 hours I started "date" on the guest - it showed that it's year *1953*, after which I couldn't start any other command (the guest was technically alive - SSH connection to it didn't die - but I couldn't do anything). # date Wed Feb 18 13:07:17 CET 2009 [let's wait ~2 hours] # date Fri May 15 10:13:14 CET 1953 # date ^C^Z [could not interrupt] Is it expected behaviour? Is it correct behaviour? -- Tomasz Chmielewski http://wpkg.org