[libvirt-users] questions on clock catchup

[Martin Kletzander]

On Thu, Mar 13, 2014 at 02:49:13AM -0400, Jincheng Miao wrote:
> In http://libvirt.org/formatdomain.html#elementsTime , we could find there are
> three attributes of catchup tickpolicy: limit, threshold and slew.
>
> "
> The catchup element has three optional attributes, each a positive integer.
> The attributes are threshold, slew, and limit.
> "
> The xml format likes:
>   <clock offset='utc'>
>     <timer name='rtc' tickpolicy='catchup'>
>       <catchup slew='123'/> or <catchup threshold='123'/> or <catchup limit='123'/>
>     </timer>
>   </clock>
>
> But there is no further explanation.
> Does anyone know what's the meaning of these attributes ?
>

What an interesting question.  At first I thought the meanings are the
same as in ntpd(1) and other time-synchonizing apps.  But then I
looked into the code to see what we're passing to hypervisors and it
seems like since 2010, when this was added, these values were never
used.

[Cc-ing Laine as he is the author of commit 8bf6799b]

I can't be sure though.  Laine, do you recall any usage of these
settings?

Martin
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