[ntp:questions] Re: ntpd, boot time, and hot plugging
David L. Mills
mills at udel.edu
Fri Feb 4 04:39:00 UTC 2005
I don't think you have the model right. The ntpd never "backgrounds
itself", but keeps on ticking according to a state machine which
controls whether or not to do a direct frequency measurement rather than
the usual incremental feedback loop, which depends on whether the
frequecy file is present. The only thing the -g does is exit the daemon
when the clock is first set.
Tom Smith wrote:
> Brad Knowles wrote:
>> At 12:30 AM +0000 2005-02-04, Tom Smith wrote:
>>> 1) step the clock to a "good enough" time
>>> do this within a few seconds
>>> block while doing it
>>> don't touch/change the pre-computed drift while doing this
>>> 2) start ntpd
>>> 3) start time-dependent services
>> Thinking about this some more, what I hear you saying is that ntpd
>> should not background itself until such time as it has calculated the
>> initial offset and stepped the clock as necessary to get you within
>> normal slew distance, at which point it backgrounds itself and
>> continues normal startup operations, starts working on
>> calculating/updating the drift, etc....
>> At least, it should have this as an optional startup mode, perhaps
>> as a part of "-g".
> Bingo. And DON'T TOUCH THE DRIFT until the second phase starts.
> I'd also say that should always be the startup mode, -g or no -g
> (or at least -g should be implied during that first phase, whether
> or not it's requested for the "permanent" phase).
> Tom Smith smith at alum.mit.edu,smith at cag.lkg.hp.com
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