This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] domU clock over 23s off

On Jul 12, Saku Ytti wrote:

> On (2006-07-12 15:37 +0200), Harald Koenig wrote:
> > does running ntp in a domU disable the clock synchronisation between dom0 
> > and domU ?
> I do this:
> [ytti@xxxxxxx ~]% ssh root@xxxxxxxxxxx "cat /etc/cron.hourly/ntp-hack"
> #!/bin/sh
> PATH=/bin
> date -s $(date +%H:%M:%S) > /dev/null

thanks for the hint!  

indeed, running this on dom0 also sets the clocks for domU.

BUT: it also causes clock jumps up to 0.999 secs every our because it can't 
handle fractions of a second.   and it always steps back the time
giving a non-monotonic system time -- too bad :-(((

that's not what time syncronisation and ntp is all about...

I tried to keep the fractions of seconds but this doesn't work:

        # date -s $( date +%H:%M:%S.%N )
        date: invalid date `21:38:53.976633000'

are there other methods  to trigger the time sync (push) between 
dom0 and domU without (re-) setting the system time in dom0 ? 

looks like I have to live with a jumpy time for now :-(

thanks for your help,

Harald Koenig
"I hope to die                                      ___       _____
before I *have* to use Microsoft Word.",           0--,|    /OOOOOOO\
Donald E. Knuth, 02-Oct-2001 in Tuebingen.        <_/  /  /OOOOOOOOOOO\
                                                    \  \/OOOOOOOOOOOOOOO\
                                                      \ OOOOOOOOOOOOOOOOO|//
Harald Koenig                                          \/\/\/\/\/\/\/\/\/
science+computing ag                                    //  /     \\  \
koenig@xxxxxxxxxxxxxxxxxxxx                            ^^^^^       ^^^^^

Xen-devel mailing list