From: Gleb Natapov <gleb@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: qemu-devel@nongnu.org, Jan Kiszka <jan.kiszka@siemens.com>,
Michael Roth <mdroth@linux.vnet.ibm.com>,
Luiz Capitulino <lcapitulino@redhat.com>,
Avi Kivity <avi@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>,
Eric Blake <eblake@redhat.com>
Subject: Re: [Qemu-devel] Rethinking missed tick catchup
Date: Thu, 13 Sep 2012 17:48:11 +0300 [thread overview]
Message-ID: <20120913144811.GL20907@redhat.com> (raw)
In-Reply-To: <87boha7zyx.fsf@codemonkey.ws>
On Thu, Sep 13, 2012 at 09:35:18AM -0500, Anthony Liguori wrote:
> Gleb Natapov <gleb@redhat.com> writes:
>
> > On Thu, Sep 13, 2012 at 09:06:29AM -0500, Anthony Liguori wrote:
> >> "Daniel P. Berrange" <berrange@redhat.com> writes:
> >>
> >> I think it's better for QEMU to talk to qemu-ga. We can tell when a large
> >> period of time has passed in QEMU because we'll accumulate a large
> >> number of missed ticks.
> >>
> > With RTC configured to use vm clock we will not.
>
> Not for host suspend. For stop and live migration, we stop vm_clock.
> But QEMU isn't aware of host suspend so vm_clock cannot be stopped.
>
Hmm, true. What about hooking into suspend and doing vmstop during
suspend.
> >> This could happen because of stop, host suspend, live migration to a
> >> file, etc.
> >>
> >> It's much easier for us to call into qemu-ga to do the time correction
> >> whenever this event occurs than to try and have libvirt figure out when
> >> it's necessary.
> > And if guest does not have qemu-ga what is better inject interrupts like
> > crazy for next 2 minutes or leave guest with incorrect time?
>
> Yes, at least that's fixable by the end-user. QEMU consuming 100% CPU
> for a prolonged period of time isn't fixable.
>
You mean yes to "leave guest with incorrect time"? QEMU will still
consume 100% of cpu for some time calling qemu_timer callback millions
times. timedrift code is not the right level to fix that.
--
Gleb.
next prev parent reply other threads:[~2012-09-13 14:48 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-12 13:54 [Qemu-devel] Rethinking missed tick catchup Anthony Liguori
2012-09-12 14:21 ` Jan Kiszka
2012-09-12 14:44 ` Anthony Liguori
2012-09-12 14:50 ` Jan Kiszka
2012-09-12 15:06 ` Gleb Natapov
2012-09-12 15:42 ` Jan Kiszka
2012-09-12 15:45 ` Gleb Natapov
2012-09-12 16:16 ` Gleb Natapov
2012-09-12 15:15 ` Gleb Natapov
2012-09-12 18:19 ` Anthony Liguori
2012-09-13 10:49 ` Gleb Natapov
2012-09-13 13:14 ` Eric Blake
2012-09-13 13:28 ` Daniel P. Berrange
2012-09-13 14:06 ` Anthony Liguori
2012-09-13 14:22 ` Gleb Natapov
2012-09-13 14:34 ` Avi Kivity
2012-09-13 14:42 ` Eric Blake
2012-09-13 15:40 ` Avi Kivity
2012-09-13 15:50 ` Anthony Liguori
2012-09-13 15:53 ` Avi Kivity
2012-09-13 18:27 ` Anthony Liguori
2012-09-16 10:05 ` Avi Kivity
2012-09-16 14:37 ` Anthony Liguori
2012-09-19 15:34 ` Avi Kivity
2012-09-19 16:37 ` Gleb Natapov
2012-09-19 16:44 ` Avi Kivity
2012-09-19 16:55 ` Gleb Natapov
2012-09-19 16:57 ` Avi Kivity
2012-09-13 14:35 ` Anthony Liguori
2012-09-13 14:48 ` Gleb Natapov [this message]
2012-09-13 15:51 ` Avi Kivity
2012-09-13 15:56 ` Anthony Liguori
2012-09-13 16:06 ` Gleb Natapov
2012-09-13 18:33 ` Anthony Liguori
2012-09-13 18:56 ` Gleb Natapov
2012-09-13 20:06 ` Anthony Liguori
2012-09-13 16:08 ` Avi Kivity
2012-09-13 13:47 ` Gleb Natapov
2012-09-12 16:27 ` Stefan Weil
2012-09-12 16:45 ` Gleb Natapov
2012-09-12 17:30 ` Stefan Weil
2012-09-12 18:13 ` Gleb Natapov
2012-09-12 19:45 ` Stefan Weil
2012-09-13 10:50 ` Gleb Natapov
2012-09-12 20:06 ` Michael Roth
2012-09-12 17:23 ` Luiz Capitulino
-- strict thread matches above, loose matches on Subject: below --
2012-09-12 18:03 Clemens Kolbitsch
2012-09-13 6:25 ` Paolo Bonzini
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