[ntp:questions] NTP not syncing
unruh at invalid.ca
Thu Dec 5 21:48:41 UTC 2013
On 2013-12-05, antonio.marcheselli at gmail.com <antonio.marcheselli at gmail.com> wrote:
>> The problem with google groups is a) Many have filtered it out because
>> of spam so your audience is smaller, and b) it inserts a blank line
>> between every line of text it quotes, making threads raplidly unreadable
>> for everyone else. It may hide this from you, I donot know.
> I understand and I apologise but I'm with a small netbook at the moment and I can't do better. I'm trying to clean the posts before posting them back.
> I'll see if I can fine an alternative. Thanks for your understanding in the meantime.
>> -258 IS pretty high. On what kind of machine? What operating system?
> Same machine that was before! Supermicro motherboard, debian 5.0.7
>> The computer has to calibrate the timer interrupts on bootup. That
>> calibration can be variable. For older versions of the Linux kernel that
>> calibration was very variable, of the order that you are seeing. That
>> seems to have been fixed on the more recent kernels.
> But I only restarted the ntp service, I did not reboot the server.
> As it's been said, I'm concerned that if the calibration can drift by 200ppm I may end up over the 500ppm boundary.
> But I understand that the drift file will change between reboots, but it will then stabilise. Now the power saving is disabled I don't see the drift changing over time, which should be good?
Yes, power saving is definitely a problem if your system clock is using
tsc as the clock. The number of instructin cycles per secong changes
under powersaving and thus the system clock rate changes by huge
amounts. ( the powersaving could cause the cpu to go half as fast). The
only thing to do is to use some other counter as the system clock (HPET
should be better shouldn't it?-- I donot know how it behaves under
More information about the questions