From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:33917) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TCAdO-0003FO-Ts for qemu-devel@nongnu.org; Thu, 13 Sep 2012 10:43:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TCAdI-0005An-8h for qemu-devel@nongnu.org; Thu, 13 Sep 2012 10:43:14 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33073) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TCAdI-0005AY-07 for qemu-devel@nongnu.org; Thu, 13 Sep 2012 10:43:08 -0400 Message-ID: <5051F0CB.9040303@redhat.com> Date: Thu, 13 Sep 2012 08:42:19 -0600 From: Eric Blake MIME-Version: 1.0 References: <87pq5r5otp.fsf@codemonkey.ws> <20120912151549.GT20907@redhat.com> <87y5kfrtne.fsf@codemonkey.ws> <20120913104940.GA20907@redhat.com> <5051DC20.4090204@redhat.com> <20120913132804.GO7767@redhat.com> <87r4q6xbiy.fsf@codemonkey.ws> <20120913142228.GK20907@redhat.com> <5051EF0D.4070109@redhat.com> In-Reply-To: <5051EF0D.4070109@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="------------enigFCD50AF189F2127E05FF95A4" Subject: Re: [Qemu-devel] Rethinking missed tick catchup List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Gleb Natapov , Jan Kiszka , Michael Roth , qemu-devel@nongnu.org, Anthony Liguori , Paolo Bonzini , Luiz Capitulino This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigFCD50AF189F2127E05FF95A4 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 09/13/2012 08:34 AM, Avi Kivity wrote: > On 09/13/2012 05:22 PM, Gleb Natapov wrote: >>> >>> It's much easier for us to call into qemu-ga to do the time correctio= n >>> whenever this event occurs than to try and have libvirt figure out wh= en >>> it's necessary. >=20 >> And if guest does not have qemu-ga what is better inject interrupts li= ke >> crazy for next 2 minutes or leave guest with incorrect time? >=20 > We can try to S3 and resume the guest. The guest will assume that it > has slept for an unknown amount of time and resync from the RTC. Just restating to make sure I'm clear: you are proposing that after host suspend and host wakeup, _then_ qemu asks the guest to go into S3 followed by an immediate resume. During the time that the guest goes into S3, its clock is way off; but then the immediate resume will be the necessary kick to the guest to resync, and at that point, the guest can assume that it has been off since the host originally suspended (rather than the instant window where qemu actually bounced S3 after the host had already resumed). > This may not work for really old server oriented guests. S3 requires guest cooperation, period. But so does qemu-ga. It's better than nothing, and we can't get perfection without guest cooperatio= n. --=20 Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --------------enigFCD50AF189F2127E05FF95A4 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Public key at http://people.redhat.com/eblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://www.enigmail.net/ iQEcBAEBCAAGBQJQUfDLAAoJEKeha0olJ0Nq168IAK9N3z29lfiFEgott9vgMYp0 iRpzPIidsoNGQI+QCl/m3j4G25gSzV5sWhMI86XtodQ0rx4KpO65INSDoO2V1Qlv SCkmEtHDryah2AFQDWjPFONm3V8Cac8hfhrYRw9c17KOUHIeYStBguuv32l9VjhG mCMeYFac7jdvzh4LQDsezLVWW+3pnWj8sqvubbHfwaoiylOwvp+Go2F1vgKfmivi edQVvVUE3zxnQzE2n2Neh0EeiGRT+sjgnd3xBFnXVJVVrMcJJ5ZZKClt6On3z4j5 d1HJzpAb6DpU4Cb5IADfdV+gdXbbGcNaOGbNT2Dgn8n7byY7uU5szAZe8RSrQNs= =qSoG -----END PGP SIGNATURE----- --------------enigFCD50AF189F2127E05FF95A4--