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Re: [Xen-devel] Re: XenParavirtOps wiki page updates

To: Ferenc Wagner <wferi@xxxxxxx>
Subject: Re: [Xen-devel] Re: XenParavirtOps wiki page updates
From: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Date: Fri, 19 Dec 2008 17:32:16 -0800
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Ferenc Wagner wrote:
Hmm, my last data points are from the summer, but since people keep
constantly asking on the users' list how to do this, I assumed things
didn't change.  Back then ntpd was unable to change the domU clock, it
was constantly drifting away from the current time.

Ah. I've never tested it, but I've never got a bug report about it either. The Xen clocksource's rate should be tuneable down to ~1ppm, which should be fine for ntp.

  Also, when the
procfs settings (like independent_wallclock) disappeared I got the
impression that the system times are now unconditionally synced.

No, the opposite - its never synced, except at domain boot.

Probably I'm just confused and all is well now...  I'll set up and
test this again.  Thanks for the hint!

Please keep me informed. RH has been shipping pvops kernels for a while now, and their stock install starts ntp. I would have assumed that I'd have heard about any time sync problems by now...


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