"runtime went backwards" message in logs

Koen Martens fbsd at metro.cx
Fri Dec 30 02:29:43 PST 2005

Julian H. Stacey wrote:

>>PS. Not sure if this have anything to do with it (the message mentions CPU
>>time, not the clock), but I'm running a ntp daemon, to synchronize time...
>Highly likely it has a Lot to do with it :-) Maybe the master time
>server had `date` run manually, or otherwise shifted, or came back
>on net after an outage, & the systems noticed drifted time & corrected etc.
>	man ntpd
>	man ntp.conf 
>	etc :-)
AFAIK, under normal circumstances ntpd should never reset the current 
time the hard way. Ntpd slows down (slews) or increases (steps) the 
speed of your clock, such that it will catch up or fall behind enough to 
become in line with the ntp servers it is listening to (since resetting 
the time the hard way is usually not a good idea; think makefiles, 
cronjobs that could run twice, etc..). You could check out the -x flag 
to nptd, to prevent setting the clock the hard way all together (since 
network congestion and stuff like that might result in ntpd setting the 
clock the hard way).



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