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Re: Slow clock on Xen 4.8 after upgrade




On Thu, 7 Jun 2018 19:32:35 +0100 Mike said:

[--8<--]

> In the end I used adjtimex -t 10065 -f 3058784 to speed the clock up a
> bit and that has allowed NTP to be able to keep it under control.
> 
> So the issue with the slow clock appears to have been compenstated for
> but I'd be intersted to know what actually caused it.  I've drawn a bit
> of a blank on that one and would be grateful if anyone could offer any
> thoughts?

Could there be a race condition between hwclock(8) and adjtimex?

IOW, there is a possibility that perhaps there was a drift rate set by hwclock
and this was the cause of excessive drift. Now that adjtimex counter balances
hwclock by an opposite drift rate, it can result in hwclock and adjtimex
fighting against each other. Just a possibility.

I would have checked /etc/adjtime to ensure that no drift ratio set by hwclock.
More info about hwclock drift setting and /etc/adjtime format in hwclock man
page.

Regards
-- 
Abdullah Ramazanoğlu