[ntp:questions] Re: tinker step 0 (always slew) and kernel time discipline
harvell at nortel.com
Fri Sep 22 16:58:33 UTC 2006
David L. Mills wrote:
> "disable kernel" does exactly and precisely that. In that case
> corrections are handled as if the kernel code does not exist.
> Ordinarily, to disable the step correction also disables the kernel.
> Your "tinker step 0" exposed a bug, now fixed, in which the kernel was
> not automatically disabled in that case.
In the Feb, 2005 thread, you stated that the kernel was disabled exactly if the amount of the correction was >0.5 seconds and hand nothing to do with the step threshold.
Do you happen to know in which release of ntp the behavior was changed to what you are describing now?
> Joe Harvell wrote:
>> I have an application that is sensitive to step corrections and am
>> considering using 'tinker step 0' to disable them altogether.
>> However, I noticed a thread on this topic in February 2005
>> that suggested setting 'tinker step 0' without explicitly using
>> 'disable kernel' will essentially yield unpredictable behavior.
>> So what does disable kernel do? Does it disable the NHPFL algorithm?
>> Is this algorithm synonomous with the "kernel time discipline?" So
>> when "disable kernel" has been used, how is the clock frequency
>> adjusted? Also, why is the kernel time discipline disabled when a
>> correction of > 0.5 seconds is required?
>> Joe Harvell
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