Re: Question: Timekeeping between Host and Guest with NTP

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Thank you for your comment,

(2012/08/24 3:13), Marcelo Tosatti wrote:
<snip>
NTP should be running in the guest so as to synchronize the guest
time-of-day clocks to UTC.

kvmclock exposes the monotonic clock from the host. The frequency
of the host monotonic clock is corrected by host ntpd. This is
probably where the confusion comes from.

That is no guarantee that time-of-day clocks in the guest are
synchronized to UTC or even that clock frequency visible to userspace
applications in the guest is equal to the monotonic clock frequency
of the host.

I understood your comment except one point.
We know that the frequency of host monotonic clock is kept
accurate by host ntpd and that kvmclock shows it to the guest.
Doesn't this mean that applications in the guest can see the accurate
clock frequency provided by the host?

Sincerely,

--
Aritoki TAKADA
aritoki.takada.jt@xxxxxxxxxxx
Hitachi, Ltd., Yokohama Research Laboratory
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