From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:59069) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TC9lB-0002Ly-Qg for qemu-devel@nongnu.org; Thu, 13 Sep 2012 09:47:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TC9l5-0002MB-VQ for qemu-devel@nongnu.org; Thu, 13 Sep 2012 09:47:13 -0400 Received: from mx1.redhat.com ([209.132.183.28]:19324) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TC9l5-0002M6-Lo for qemu-devel@nongnu.org; Thu, 13 Sep 2012 09:47:07 -0400 Date: Thu, 13 Sep 2012 16:47:02 +0300 From: Gleb Natapov Message-ID: <20120913134702.GG20907@redhat.com> References: <87pq5r5otp.fsf@codemonkey.ws> <20120912151549.GT20907@redhat.com> <87y5kfrtne.fsf@codemonkey.ws> <20120913104940.GA20907@redhat.com> <5051DC20.4090204@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5051DC20.4090204@redhat.com> Subject: Re: [Qemu-devel] Rethinking missed tick catchup List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: qemu-devel@nongnu.org, Jan Kiszka , Michael Roth , Luiz Capitulino , Avi Kivity , Anthony Liguori , Paolo Bonzini On Thu, Sep 13, 2012 at 07:14:08AM -0600, Eric Blake wrote: > On 09/13/2012 04:49 AM, Gleb Natapov wrote: > >> They do if you hibernate your laptop. > >> > > AFAIK libvirt migrates vm into a file on hibernate. It is better to move to S3 > > (using qemu-ga) instead and migrate to file only if s3 fails. > > On host hibernate, libvirt currently does nothing to the guest. When > the host resumes, the guests see a large gap in execution. > > Libvirt would need a hook into host hibernation, to have enough time to > tell the guests to go into S3 prior to allowing the host to go into S3. > > On host reboot, libvirt currently saves guests to disk using migrate to > file. The ideal solution would be to first tell the guest to go into S3 > before migrating to file, but the migration to file STILL must occur, > because the host is about to reboot and S3 is not persistent. S3 is a > better solution than S4, in that S4 requires the guest to have enough > memory (and if it doesn't cooperate, data is lost), but with S3, even if > the guest doesn't cooperate, we can still fall back to migration to file > with the guest only losing time, but not data. > Correct, after S3 libvirt needs to migrate to file. So my AFAIK was incorrect. Is it possible to hook into host hibernation? -- Gleb.