From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Alexander Graf <agraf@suse.de>
Cc: "Alexey Kardashevskiy" <aik@ozlabs.ru>,
qemu-devel@nongnu.org, qemu-ppc@nongnu.org,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Andreas Färber" <afaerber@suse.de>,
"Paul Mackerras" <paulus@samba.org>,
"David Gibson" <david@gibson.dropbear.id.au>
Subject: Re: [Qemu-devel] [RFC PATCH] spapr: support time base offset migration
Date: Thu, 05 Sep 2013 23:36:04 +1000 [thread overview]
Message-ID: <1378388164.4321.176.camel@pasglop> (raw)
In-Reply-To: <ED53148C-F844-4894-8F21-5CD0F072C25B@suse.de>
On Thu, 2013-09-05 at 14:37 +0200, Alexander Graf wrote:
> Hrm, I think I'm starting to understand what this is about. So what we want is
>
> - timebase in guest
> - timebase frequency in guest
> - wall clock time in host
>
> That way the receiving end can then take the timebase and add (new_timebase - old_timebase) * tb_freq to the guest's time base.
>
> Which gets me to the next question. Can we modify the tb frequency in guests?
No. It's architected at 512Mhz however since P7 I think. Not sure how we
did before, it's possible that P6 was the same (at least it's sourced
from more/less the same chip TOD facility).
Cheers,
Ben.
next prev parent reply other threads:[~2013-09-05 13:36 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-03 7:31 [Qemu-devel] [RFC PATCH] spapr: support time base offset migration Alexey Kardashevskiy
2013-09-03 8:42 ` Andreas Färber
2013-09-03 9:07 ` Alexey Kardashevskiy
2013-09-03 9:22 ` Andreas Färber
2013-09-04 1:13 ` Alexey Kardashevskiy
2013-09-04 1:27 ` Alexander Graf
2013-09-05 4:30 ` David Gibson
2013-09-05 4:54 ` Alexey Kardashevskiy
2013-09-05 9:16 ` Alexander Graf
2013-09-05 9:48 ` Alexey Kardashevskiy
2013-09-05 9:58 ` Alexander Graf
2013-09-05 11:44 ` Benjamin Herrenschmidt
2013-09-05 12:37 ` Alexander Graf
2013-09-05 13:36 ` Benjamin Herrenschmidt [this message]
2013-09-05 13:39 ` Alexander Graf
2013-09-05 14:14 ` Andreas Färber
2013-09-05 14:26 ` Benjamin Herrenschmidt
2013-09-05 15:11 ` Alexander Graf
2013-09-09 2:40 ` Alexey Kardashevskiy
2013-09-09 5:50 ` Alexander Graf
2013-09-09 5:58 ` Alexey Kardashevskiy
2013-09-09 6:06 ` Alexander Graf
2013-09-09 9:29 ` Benjamin Herrenschmidt
2013-09-09 9:32 ` Alexander Graf
2013-09-09 9:38 ` Benjamin Herrenschmidt
2013-09-09 9:41 ` Alexander Graf
2013-09-13 5:20 ` David Gibson
2013-09-13 18:06 ` Alexander Graf
2013-09-05 11:42 ` Benjamin Herrenschmidt
2013-09-05 12:09 ` Alexey Kardashevskiy
2013-09-06 3:00 ` David Gibson
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