From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: [XEN-3.4] pv_ops dom0 time/clock handling Date: Wed, 27 May 2009 13:31:23 -0700 Message-ID: <4A1DA31B.5090503@goop.org> References: <4A1A6B5E.3010602@dschroeder.info> <4A1CBCA1.10301@goop.org> <4A1CEDBB.10505@dschroeder.info> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4A1CEDBB.10505@dschroeder.info> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Daniel Schroeder Cc: "xen-devel@lists.xensource.com" , Keir Fraser List-Id: xen-devel@lists.xenproject.org Daniel Schroeder wrote: > Wed May 27 09:33:12 CEST 2009 > Mi Mai 27 11:33:13 CEST 2009 > That does look like some kind of TZ issue, but I'm not sure where it would be. > btw: i have checked with 32 bit pvops and 64 bit pvops dom0 and the time > in the domU is correct with the 64bit pvops dom0 kernel...this wasnt > the same domU...so, next step for me, is to copy the domU to the 64bit > system and try again...to verify, that this only happens for me with > 32bit pvops dom0... > How odd. >> One difference between pvops time handling and the -xen kernels, is that >> they defaulted to slaving the domU time off the hypervisor at all times, >> so a system time change would propagate into guests. I don't implement >> that in pvops kernels, so they'll maintain independent time unless you >> explicitly sync with some mechanism like ntp. >> > hmm...does this mean, that i have to use ntp in domU if i use the pvops > kernel? Because time changes in dom0 doesnt propagate into domUs? > It will set its initial time-of-day clock from the hypervisor's at boot, but then proceed independently (but the timebase is derived from the hypervisor's clock). If you want it to track a reference, you need to run ntp. J