From mboxrd@z Thu Jan 1 00:00:00 1970 From: Espen Berg Subject: Re: Timedrift in KVM guests after livemigration. Date: Mon, 19 Apr 2010 11:21:47 +0200 Message-ID: <4BCC20AB.3090908@monsternett.no> References: <4BC6C1B1.5010206@monsternett.no> <4BCA1164.1030808@monsternett.no> <4BCA1756.6060800@msgid.tls.msk.ru> <4BCA4296.2080608@monsternett.no> <4BCACF6E.4010108@redhat.com> <20100418095659.GC4550@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: kvm@vger.kernel.org Return-path: Received: from mail2.monsternett.no ([217.171.192.11]:45982 "EHLO mail.monsternett.no" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752067Ab0DSJVx (ORCPT ); Mon, 19 Apr 2010 05:21:53 -0400 Received: from localhost (filter.monsternett.no [217.171.192.14]) by mail.monsternett.no (Postfix) with ESMTP id 949C2C09BDA8 for ; Mon, 19 Apr 2010 11:21:51 +0200 (CEST) Received: from mail.monsternett.no ([217.171.192.10]) by localhost (filter.monsternett.no [217.171.192.14]) (amavisd-new, port 10024) with ESMTP id 1PMOAzNBg1TQ for ; Mon, 19 Apr 2010 11:21:48 +0200 (CEST) Received: from [217.171.199.6] (ws14.monsternett.no [217.171.199.6]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.monsternett.no (Postfix) with ESMTPSA id E442FC09BDA4 for ; Mon, 19 Apr 2010 11:21:48 +0200 (CEST) In-Reply-To: <20100418095659.GC4550@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Den 18.04.2010 11:56, skrev Gleb Natapov: >> That's two different things here: >> The issue that Espen is reporting is that the hosts have different >> frequency and guests that relay on the tsc as a source clock will >> notice that post migration. The is indeed a problem that -tdf does >> not solve. -tdf only adds compensation for the RTC clock emulation. >> > It's -rtc-td-hack. -tdf does pit compensation, but since usually kernel > pit is used it does nothing. So this "hack" will not solve our problem? Espen