[ntp:questions] ntp too agressive on clock changes

unruh unruh at invalid.ca
Mon Apr 15 20:53:25 UTC 2013

On 2013-04-15, website.reader3 at gmail.com <website.reader3 at gmail.com> wrote:
> Unruh:
> I am getting the clock changed to a very high accuracy RTC, which should clean up the jitters.

RTC has nothing to do with ntpd. It is the system clock which ntpd
disciplines. This is not really a clock, but rather is a counter
(system instructions, hpet,...). The
RTC is used ONLY at bootup. During normal running, the kernel will, ever
11 min, set the rtc to the system clock which plays havoc with say,
hwclock which can measure the system clock rate drift and compensate for

Perhaps what you are doing it reading the rtc and seeing that 11 min
resetting of that clock. You should never have to use the rtc during
normal operation. 

> I think the nanosleep call is to blame here, not htp.

?? what do you mean? Where is nanosleep coming in to play?

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