From: Keir Fraser <keir@xensource.com>
To: John Levon <levon@movementarian.org>
Cc: xen-devel@lists.xensource.com
Subject: Re: System time monotonicity
Date: Tue, 27 Mar 2007 11:47:40 +0100 [thread overview]
Message-ID: <C22EB4DC.C47E%keir@xensource.com> (raw)
In-Reply-To: <20070326200447.GA3730@totally.trollied.org.uk>
On 26/3/07 21:04, "John Levon" <levon@movementarian.org> wrote:
>> Small backwards time deltas are possible from the current time code. You'll
>> have to filter them out yourself if you can't deal with them. We could add
>> extra code in Xen to stop this happening for any individual VCPU
>
> Some instrumentation indicated that we had cross-VCPU jitter of
> significant deltas, ~18us at worst. Though the instrumentation wasn't
> completely reliable so that might not be accurate.
I should add that time synchronisation is currently broken in xen-unstable,
and has been for about two weeks. I just checked in a patch (based on one
from Jan Beulich) to fix this (changeset 14573:ba9d3fd4ee4b).
-- Keir
next prev parent reply other threads:[~2007-03-27 10:47 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-26 18:23 System time monotonicity John Levon
2007-03-26 18:47 ` Keir Fraser
2007-03-26 20:04 ` John Levon
2007-03-27 10:47 ` Keir Fraser [this message]
2007-04-03 14:03 ` John Levon
2007-03-26 18:50 ` Ian Pratt
2007-03-26 18:59 ` Keir Fraser
2007-03-26 20:14 ` John Levon
2007-03-26 21:55 ` Ian Pratt
2007-03-27 0:27 ` Keir Fraser
-- strict thread matches above, loose matches on Subject: below --
2007-04-03 14:36 Ian Pratt
2007-04-03 14:57 ` John Levon
2007-04-03 17:51 Ian Pratt
2008-04-08 16:34 Dan Magenheimer
2008-04-08 16:42 ` Keir Fraser
2008-04-08 17:39 ` Dan Magenheimer
2008-04-09 1:16 ` Tian, Kevin
2008-04-09 1:55 ` Dan Magenheimer
2008-04-09 3:20 ` Tian, Kevin
2008-04-09 12:42 ` Ian Pratt
2008-04-09 14:25 ` Dan Magenheimer
2008-04-09 14:41 ` Keir Fraser
2008-04-09 16:33 ` Dan Magenheimer
2008-04-09 16:40 ` Keir Fraser
2008-04-09 18:36 ` Dan Magenheimer
2008-04-10 7:08 ` Keir Fraser
2008-04-10 21:27 ` Dan Magenheimer
2008-04-11 6:48 ` Keir Fraser
2008-04-11 22:05 ` Dan Magenheimer
[not found] <47FFC37A.4060402@virtualiron.com>
2008-04-11 21:20 ` Keir Fraser
2008-04-11 21:41 ` Keir Fraser
2008-04-11 22:58 ` Dave Winchell
2008-04-12 7:09 ` Keir Fraser
2008-04-21 19:26 ` Dan Magenheimer
2008-04-21 19:31 ` Keir Fraser
2008-04-11 22:22 ` Dan Magenheimer
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