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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


  reply	other threads:[~2007-12-19 15:41 UTC|newest]

Thread overview: 28+ 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 17:20 ` Avi Kivity
2007-12-18 22:19 ` Ingo Molnar
2007-12-18 22:19   ` Ingo Molnar
2007-12-19  6:33   ` Avi Kivity
2007-12-19  6:33     ` Avi Kivity
2007-12-19 11:19     ` [kvm-devel] " Avi Kivity
2007-12-19 11:19       ` Avi Kivity
2007-12-19 11:39       ` [kvm-devel] " Avi Kivity
2007-12-19 14:06         ` Ingo Molnar
2007-12-19 14:06           ` Ingo Molnar
2007-12-19 14:27           ` [kvm-devel] " Avi Kivity
2007-12-19 15:32             ` Glauber de Oliveira Costa
2007-12-19 15:32               ` Glauber de Oliveira Costa
2007-12-19 15:41               ` Avi Kivity [this message]
2007-12-20 10:34                 ` [kvm-devel] " Glauber de Oliveira Costa
2007-12-20 10:34                   ` Glauber de Oliveira Costa
2007-12-19 16:55               ` [kvm-devel] " Amit Shah
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 17:04                   ` Dor Laor
2007-12-19 17:09                   ` [kvm-devel] " Avi Kivity
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 14:53             ` Avi Kivity
2007-12-19 15:09             ` [kvm-devel] " Ingo Molnar
2007-12-19 15:21               ` Avi Kivity
2007-12-19 15:21                 ` Avi Kivity

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