From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: kvm: odd time values since "kvmclock: set scheduler clock stable" Date: Mon, 18 May 2015 21:13:31 -0300 Message-ID: <20150519001331.GA15517@amt.cnet> References: <55528A04.2060404@oracle.com> <20150518223936.GA4486@amt.cnet> <555A79A5.608@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: KVM General , LKML , Paolo Bonzini , lcapitulino@redhat.com To: Sasha Levin Return-path: Content-Disposition: inline In-Reply-To: <555A79A5.608@oracle.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org GOn Mon, May 18, 2015 at 07:45:41PM -0400, Sasha Levin wrote: > On 05/18/2015 06:39 PM, Marcelo Tosatti wrote: > > On Tue, May 12, 2015 at 07:17:24PM -0400, Sasha Levin wrote: > >> Hi all, > >> > >> I'm seeing odd jump in time values during boot of a KVM guest: > >> > >> [...] > >> [ 0.000000] tsc: Detected 2260.998 MHz processor > >> [3376355.247558] Calibrating delay loop (skipped) preset value.. > >> [...] > >> > >> I've bisected it to: > > > > Paolo, Sasha, > > > > Although this might seem undesirable, there is no requirement > > for sched_clock to initialize at 0: > > > > " > > * > > * There is no strict promise about the base, although it tends to start > > * at 0 on boot (but people really shouldn't rely on that). > > * > > " > > > > Sasha, are you seeing any problem other than the apparent time jump? > > Nope, but I've looked at it again and it seems that it jumps to the host's > clock (that is, in the example above the 3376355 value was the host's clock > value). > > > Thanks, > Sasha Sasha, thats right. Its the host monotonic clock.