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Re: [Xen-devel] Time went backwards

To: Niraj Tolia <ntolia@xxxxxxxxx>, Xen Developers <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] Time went backwards
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Fri, 15 Feb 2008 08:22:00 +0000
Cc: Mark Langsdorf <mark.langsdorf@xxxxxxx>
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On 15/2/08 00:18, "Niraj Tolia" <ntolia@xxxxxxxxx> wrote:

> I have been experimenting with frequency scaling on a 4 core (2
> sockets) AMD Opteron processors. The versions of Xen I have tested
> with include xen-testing as well as xen-unstable (cs 17042). For both
> these versions, I am using the linux 2.6.18-8 tree and have passed
> cpufreq=dom0-kernel to the xen command line.
> However, I get plenty of "Time went backwards" whenever I attempt to
> change frequency. Does anyone know how this can be fixed?
> % grep name /proc/cpuinfo | head -1
> model name      : Dual-Core AMD Opteron(tm) Processor 2216 HE
> powernow-k8: error - out of sync, fix 0x10 0x10, vid 0xe 0xc
> powernow-k8: error - out of sync, fix 0x10 0x2, vid 0xc 0x12

Presumably you have cpufreq=dom0-kernel on your Xen command line? Apart from
that noone else has reported 'out of sync' messages from the powernow
driver. Mark may have some idea what that could be about.

 -- Keir

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