So what's the algorithm?  If the time changes by more than half an hour (between the heartbeat sampling the clock) it's a clock change but if its less than half an hour its clock drift.  What threshold value would you use?  10 minutes? Half an hour?  A minute? I'm interested in opinions here This is easy to add and a good idea, but getting that magic constant right is important.

On Wed, Jan 12, 2011 at 4:24 AM, Igor Stasenko <siguctua@gmail.com> wrote:

Well, putting the CMOS stuff aside,
i really don't like that VM could hang indefinitely if user will
adjust the clock settings.

On 12 January 2011 13:22, Levente Uzonyi <leves@elte.hu> wrote:
>
> On Wed, 12 Jan 2011, Frank Shearar wrote:
>
>>
>> Yes, Windows like to set the CMOS clock to local time, and Linux likes to
>> use UTC.
>>
>> My brother recently ran into a similar problem with a FreeBSD machine
>> running as a guest inside a Windows host. He had to touch
>> /etc/wall_cmos_clock to fix it.
>>
>> From the adjkerntz man page:
>>
>> If the file /etc/wall_cmos_clock exists, it means that CMOS clock keeps
>> local time (MS-DOS and MS-Windows compatible mode).  If that file does not
>> exist, it means that the CMOS clock keeps UTC time.
>>
>> Maybe there's a similar Linux/Mac fix?
>
> Yes, there is, but different linux distributions have different files IIRC.
> Btw, if you tell linux to assume that the hardware clock stores the local
> time, you'll still have problems after daylight saving related time changes,
> because both OSs will adjust the clock.
>
>
> Levente
>
>>
>> frank
>>
>> On 2011/01/12 01:18, Chris Muller wrote:
>>>
>>> Every time I jump back and forth from Windows to Linux on my primary
>>> laptop, the clock is wrong...
>>>
>>> On Tue, Jan 11, 2011 at 4:37 PM, Igor Stasenko<siguctua@gmail.com>
>>>  wrote:
>>>>
>>>> Yesterday on my comp two separate running images are hung
>>>> simultaneously, while i were doing something completely outside of
>>>> them.
>>>>
>>>> And now during reading  the sqUnixHeartBeat.c:
>>>>
>>>>
>>>>        /* The native clock may go backwards, e.g. due to NTP
>>>> adjustments, although
>>>>         * why it can't avoid small backward steps itself, I don't know.
>>>> Simply
>>>>         * ignore backward steps and wait until the clock catches up
>>>> again.  Of
>>>>         * course this will cause problems if the clock is manually
>>>> adjusted.  To
>>>>         * which the doctor says, "don't do that".
>>>>         */
>>>>
>>>> i start recalling that yesterday i adjusted clock back by 1 hour,
>>>> because after installing a windoze in dual boot it was set it wrongly.
>>>>
>>>> But of course it could be anything else :)
>>>>
>>>> --
>>>> Best regards,
>>>> Igor Stasenko AKA sig.
>>>>
>>>
>>>
>>
>>
>



--
Best regards,
Igor Stasenko AKA sig.