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[Xen-devel] Re: Bizarre pv kernel ultra-high frequency rdtsc?!?

To: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>, Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: [Xen-devel] Re: Bizarre pv kernel ultra-high frequency rdtsc?!?
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Sat, 21 Nov 2009 21:45:24 +0000
Cc: "Xen-Devel \(E-mail\)" <xen-devel@xxxxxxxxxxxxxxxxxxx>
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On 20/11/2009 23:45, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote:

> -        _u.tsc_timestamp     = t->stime_local_stamp;
> -        _u.system_time       = t->stime_local_stamp;
> +        _u.tsc_timestamp     = t->stime_local_stamp - BIG_OFFSET;
> +        _u.system_time       = t->stime_local_stamp - BIG_OFFSET;

Ah, the line above is the bug. You should be subtracting BIG_OFFSET from
_u.tsc_timestamp only. Leave _u.system_time as it is. That'll fix all your
observed problems.

 -- Keir

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