From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: kvm linux guest hanging for minutes at a time Date: Thu, 11 Aug 2011 09:38:57 +0300 Message-ID: <4E437901.9070207@redhat.com> References: <201108070806.59194.thomas@fjellstrom.ca> <201108090603.18151.thomas@fjellstrom.ca> <4E4129C3.3020200@redhat.com> <201108090831.48423.thomas@fjellstrom.ca> <4E414615.8030201@redhat.com> <4E41534F.1010502@letterboxes.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: thomas@fjellstrom.ca, "kvm@vger.kernel.org" To: Nick Return-path: Received: from mx1.redhat.com ([209.132.183.28]:47315 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751116Ab1HKGjF (ORCPT ); Thu, 11 Aug 2011 02:39:05 -0400 In-Reply-To: <4E41534F.1010502@letterboxes.org> Sender: kvm-owner@vger.kernel.org List-ID: On 08/09/2011 06:33 PM, Nick wrote: > Hi, > > Just joined this list, looking for leads to solve a similar-sounding problem > (guest processes hanging for seconds or minutes when host IO load is high). > I'll say more in a separate email, but I caught the end of this thread and > wanted to ask about kvm-clock. > > Naively I'd have thought that using the wrong clock would not actually *cause* > hangs like this. Or is that what you're implying? > > Using the wrong clock easily causes hangs. The system schedules a wakeup in 3 ms, wrong clock causes it to wakeup in 3 years, you get a hang for (3 years - 3 ms). -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.