From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: Make QEmu HPET disabled by default for KVM? Date: Sun, 14 Mar 2010 09:10:38 +0200 Message-ID: <20100314071038.GC19233@redhat.com> References: <201003111552.54293.sheng@linux.intel.com> <4B98A294.7010104@redhat.com> <20100311190807.GD17264@amt.cnet> <4B9C8ACE.4090400@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Marcelo Tosatti , Sheng Yang , kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:18474 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752044Ab0CNHKk (ORCPT ); Sun, 14 Mar 2010 03:10:40 -0400 Content-Disposition: inline In-Reply-To: <4B9C8ACE.4090400@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Sun, Mar 14, 2010 at 09:05:50AM +0200, Avi Kivity wrote: > On 03/11/2010 09:08 PM, Marcelo Tosatti wrote: > > > >> > >>>I have kept --no-hpet in my setup for > >>>months... > >>Any details about the problems? HPET is important to some guests. > >As Gleb mentioned in the other thread, reinjection will introduce > >another set of problems. > > > >Ideally all this timer related problems should be fixed by correlating > >timer interrupts and time source reads. > > This still needs reinjection (or slewing of the timer frequency). > Correlation doesn't fix drift. > But only when all time sources are synchronised and correlated with interrupts we can slew time frequency without guest noticing (and only if guest disables NTP) > >Since one already has to use special timer parameters (-rtc-td-hack, > >-no-kvm-pit-reinjection), using -no-hpet for problematic Linux > >guests seems fine? > > Depends on how common the problematic ones are. If they're common, > better to have a generic fix. > > -- > error compiling committee.c: too many arguments to function -- Gleb.