time drift w/virtualbox: FreeBSD Host -> FreeBSD guest w/ guest additions active

[Marc Fournier]

Done:

===
:~ # sysctl kern.eventtimer.idletick=1
kern.eventtimer.idletick: 0 -> 1
:~ # ntpdate time.nist.gov
 4 Dec 14:02:11 ntpdate[30137]: step time server 128.138.141.172 offset 239.820647 sec
:~ # 
===

And, already 6 secs off:

# ssh ruralcatholicradio.com date ; date
Wed Dec  4 14:03:09 EST 2013
Wed Dec  4 19:03:15 UTC 2013


On Dec 4, 2013, at 10:50 , Mikhail Tsatsenko <m.tsatsenko at gmail.com> wrote:

> 2013/12/4 Marc Fournier <mfournier at openstudent.ca>:
>> 
>> Why is this such a difficult thing to keep in sync? :(
>> 
>> I have a FreeBSD Host running 4.2.18 … Guest FreeBSD Host has Additions 4.2.18 installed ..
>> 
>> On the Host, I believe all the kernel modules are loaded properly:
>> 
>> # kldstat|grep vb
>> 6    3 0xffffffff80c59000 59da0    vboxdrv.ko
>> 8    2 0xffffffff80e20000 29f1     vboxnetflt.ko
>> 11    1 0xffffffff80e2e000 3f8a     vboxnetadp.ko
>> 
>> On the Guest, again, I believe everything is loaded:
>> 
>> # kldstat|grep vb
>> 2    1 0xffffffff80c12000 26585    vboxguest.ko
>> 
>> And the VB processes are started:
>> 
>> # ps aux | grep VB
>> root      606  0.0  0.1  32244   2144 ??  Ss    6:06PM    2:09.26 /usr/local/sbin/VBoxService
>> 
>> I don’t have ntpd running on the Guest, but have tried it with it running also ...
>> 
>> But, my time is already drifting:
>> 
>> # ssh ruralcatholicradio.com date ; date
>> Wed Dec  4 12:01:34 EST 2013
>> Wed Dec  4 17:03:17 UTC 2013
>> 
>> So, I login and run ntpdate to bring it back in sync:
>> 
>> # ntpdate time.nist.gov
>> 4 Dec 12:04:02 ntpdate[71827]: step time server 66.219.116.140 offset 102.233151 sec
>> 
>> Note that the below is run from the FreeBSD Host that the Guest is running on … same physical machine … we are perfectly in sync:
>> 
>> # ssh ruralcatholicradio.com date ; date
>> Wed Dec  4 12:04:32 EST 2013
>> Wed Dec  4 17:04:32 UTC 2013
>> 
>> An hour later, we’ve now drifted by almost 2 minutes:
>> 
>> # ssh ruralcatholicradio.com date ; date
>> Wed Dec  4 13:07:18 EST 2013
>> Wed Dec  4 18:09:16 UTC 2013
>> 
>> 
>> Its hard to believe that anyone would be using VirtualBox if it time drifted like this regularly, so I figure it has to be something that I’m doing wrong in my configuration …
>> 
>> 
>> Thoughts?
> Please try setting sysctl kern.eventtimer.idletick=1 on the guest machine.
> 
> -- 
> Mikhail