[Bug 662093] New: clock drift in Xen pvm dom0 and 2.6.34 kernel
https://bugzilla.novell.com/show_bug.cgi?id=662093 https://bugzilla.novell.com/show_bug.cgi?id=662093#c0 Summary: clock drift in Xen pvm dom0 and 2.6.34 kernel Classification: openSUSE Product: openSUSE 11.3 Version: Final Platform: x86-64 OS/Version: openSUSE 11.3 Status: NEW Severity: Normal Priority: P5 - None Component: Xen AssignedTo: jdouglas@novell.com ReportedBy: samuel.kvasnica@ims.co.at QAContact: qa@suse.de Found By: --- Blocker: --- User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13 I observe clock drift of some second per day in pvm domUs on 2.6.34.7-xen kernel, xen 4.0.1. The dom0 clock is well synced using ntpd. /proc/sys/xen/independent_wallclock is set to 0 Using the previous 2.6.31-xen kernels, the clock in domU was well in sync with dom0. Is this supposed to work in pvm domU or did it work just by accident on 2.6.31 ? Currently, as a workaround, I'm using /proc/sys/xen/independent_wallclock is set to 1 and ntpd in each domU. Both systems where I can observe this are Nehalems / Xeon3450 and Xeon5500. Reproducible: Always Steps to Reproduce: 1.description is above 2. 3. Actual Results: clock drift Expected Results: stable clocks in domU, synced to dom0 -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.
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Charles Arnold
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Jan Beulich
From an abstract point of view, yes, this is supposed to work.
However, with pv-ops not even having an independent-wallclock setting, the NTP-in-each-domain solution is the only one going forward. Between 11.2 and 11.3, we brought our time implementation close to that of pv-ops. Hence it would be helpful to know if you can observe similar divergence in pv-ops guests, as well as whether this depends on any property of the hardware you're running your guests on. Of course, we will also check whether we can spot any incorrectness in the code - please feel free to suggest code adjustments yourself. -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.
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Samuel Kvasnica
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Jan Beulich
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--- Comment #4 from Samuel Kvasnica
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Jan Beulich
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--- Comment #6 from Samuel Kvasnica
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