From: Avi Kivity <avi@qumranet.com>
To: Glauber de Oliveira Costa <glommer@gmail.com>
Cc: Avi Kivity <avi@argo.co.il>, Ingo Molnar <mingo@elte.hu>,
kvm-devel <kvm-devel@lists.sourceforge.net>,
linux-kernel <linux-kernel@vger.kernel.org>,
Chris Wright <chrisw@sous-sol.org>,
Gerd Hoffmann <kraxel@redhat.com>
Subject: Re: [kvm-devel] Guest kernel hangs in smp kvm for older kernels prior to tsc sync cleanup
Date: Wed, 19 Dec 2007 17:41:17 +0200 [thread overview]
Message-ID: <47693B9D.7080809@qumranet.com> (raw)
In-Reply-To: <5d6222a80712190732h515a63e6y49c64c0f572f044@mail.gmail.com>
Glauber de Oliveira Costa wrote:
> Changes in rate does not sound good. It's possibly what's screwing up
> my paravirt clock implementation in smp.
>
You should renew the timebase on vcpu migration, and hook cpufreq so
that changes in frequency are reflected in the timebase.
> Since the host updates guest time prior to putting vcpu to run, two
> vcpus that start running at different times will have different system
> values.
>
> Now if the vcpu that started running later probes the time first,
> we'll se the time going backwards. A constant tsc rate is the only way
> around
> my limited mind sees around the problem (besides, obviously, _not_
> making the system time per-vcpu).
>
I tried disabling frequency scaling (rmmod acpi_cpufreq) but that didn't
help my present problems.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2007-12-19 15:41 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-18 17:20 Guest kernel hangs in smp kvm for older kernels prior to tsc sync cleanup Avi Kivity
2007-12-18 22:19 ` Ingo Molnar
2007-12-19 6:33 ` Avi Kivity
2007-12-19 11:19 ` [kvm-devel] " Avi Kivity
2007-12-19 11:39 ` Avi Kivity
2007-12-19 14:06 ` Ingo Molnar
2007-12-19 14:27 ` Avi Kivity
2007-12-19 15:32 ` Glauber de Oliveira Costa
2007-12-19 15:41 ` Avi Kivity [this message]
2007-12-20 10:34 ` Glauber de Oliveira Costa
2007-12-19 16:55 ` Amit Shah
2007-12-19 17:04 ` [kvm-devel] Guest kernel hangs in smp kvm for older kernelsprior " Dor Laor
2007-12-19 17:09 ` Avi Kivity
2007-12-19 14:53 ` [kvm-devel] Guest kernel hangs in smp kvm for older kernels prior " Avi Kivity
2007-12-19 15:09 ` Ingo Molnar
2007-12-19 15:21 ` Avi Kivity
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