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