From: David Vrabel <david.vrabel@citrix.com>
To: <xen-devel@lists.xen.org>
Cc: David Vrabel <david.vrabel@citrix.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
John Stultz <john.stultz@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
<linux-kernel@vger.kernel.org>
Subject: [PATCH 0/3] x86,time,xen: maintain an accurate persistent clock in more cases
Date: Mon, 13 May 2013 18:56:05 +0100 [thread overview]
Message-ID: <1368467768-2316-1-git-send-email-david.vrabel@citrix.com> (raw)
The kernel has limited support for updating the persistent clock or
RTC when NTP is synced. This has the following limitations:
* The persistent clock is not updated on step changes. This leaves a
window where it will be incorrect (while NTP resyncs).
* On x86, the virtual platforms have persistent clocks with nanosecond
precision but this is lost in the x86_platform.set/get_wallclock()
calls. Guests may see wallclocks that are out by up to 1 second.
* Xen guests use the Xen wallclock as their persistent clock. dom0
maintains this clock so it is persistent for domUs and not dom0
itself.
These series fixes the above limitations.
Each patch in the series is independent so may be applied to their
respective trees separately.
David
next reply other threads:[~2013-05-13 17:56 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-13 17:56 David Vrabel [this message]
2013-05-13 17:56 ` [PATCH 1/3] x86: increase precision of x86_platform.get/set_wallclock() David Vrabel
2013-05-14 0:57 ` John Stultz
2013-05-14 17:52 ` John Stultz
2013-05-29 0:18 ` John Stultz
2013-05-29 12:16 ` David Vrabel
2013-05-13 17:56 ` [PATCH 2/3] timekeeping: sync persistent clock and RTC on system time step changes David Vrabel
2013-05-14 0:40 ` John Stultz
2013-05-14 9:47 ` David Vrabel
2013-05-14 17:15 ` John Stultz
2013-05-15 8:16 ` [Xen-devel] " Jan Beulich
2013-05-15 18:10 ` John Stultz
2013-05-28 18:26 ` David Vrabel
2013-05-28 18:31 ` Konrad Rzeszutek Wilk
2013-05-28 19:09 ` John Stultz
2013-05-28 19:48 ` Konrad Rzeszutek Wilk
2013-05-28 20:03 ` John Stultz
2013-05-28 20:11 ` John Stultz
2013-05-28 20:25 ` Konrad Rzeszutek Wilk
2013-05-28 20:30 ` John Stultz
2013-05-28 19:06 ` John Stultz
2013-05-13 17:56 ` [PATCH 3/3] x86/xen: sync the CMOS RTC as well as the Xen wallclock David Vrabel
2013-05-14 0:52 ` John Stultz
2013-05-14 7:57 ` [Xen-devel] " Jan Beulich
2013-05-14 15:59 ` John Stultz
2013-05-14 16:14 ` Jan Beulich
2013-05-14 16:17 ` John Stultz
2013-05-14 16:24 ` Konrad Rzeszutek Wilk
2013-05-14 16:28 ` John Stultz
2013-05-14 9:55 ` David Vrabel
2013-05-14 17:24 ` John Stultz
2013-05-14 18:00 ` David Vrabel
2013-05-14 18:03 ` John Stultz
2013-05-15 8:19 ` [Xen-devel] " Jan Beulich
2013-05-15 18:13 ` John Stultz
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