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RE: [Xen-devel] A clocksource question

To: Joanna Rutkowska <joanna@xxxxxxxxxxxxxxxxxxxxxx>, Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: RE: [Xen-devel] A clocksource question
From: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Date: Wed, 10 Mar 2010 16:07:34 -0800 (PST)
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> Clocksource tsc unstable (delta = 62752834 ns)
> hrtimer: interrupt too slow, forcing clock min delta to 412700358 ns
> > I don't remember if 3.4.2 ended up with tsc emulation, but if it does
> > you might try enabling it.
> >
> TSC emulation? But I'm running only PV guests. Not sure what do you
> mean
> by this, or how to enable it?

I don't think there is any TSC emulation (or more properly "rdtsc emulation")
in 3.4.x, certainly not without a special Xen boot option.

The TSC delta is troubling... if you hadn't said you had turned
off all power management, I would have guessed a problem with
C-state management.  Maybe Xen is discovering some power management
capability not visible in BIOS settings?

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