linux-kernel - Re: Clock jumps

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Message-ID: <4BFEEE3A.1010403@birkenwald.de>
Date:	Fri, 28 May 2010 00:12:10 +0200
From:	Bernhard Schmidt <berni@...kenwald.de>
To:	Zachary Amsden <zamsden@...hat.com>
CC:	kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: Clock jumps

On 27.05.2010 23:53, Zachary Amsden wrote:

Hello Zachary,

> I have server side fixes for this kvm-clock which seem to give me a
> stable clock on this machine, but for true SMP stability, you will need
> Glauber's guest side changes to kvmclock as well. It is impossible to
> guarantee strictly monotonic clocksource across multiple CPUs when
> frequency is dynamically changing (and also because of the C1E idle
> problems).

Is all this relevant only when the host is on TSC? Because I have seen 
these jumps when the host was on HPET and the guests were using kvm-clock.

Anyway, can you send me both patches? I'd like to try it, but I have 
completely lost track where the up-to-date patches are.

Bernhard
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