[ntp:questions] Tighter regulation?

unruh unruh at invalid.ca
Sun May 26 21:32:54 UTC 2013


On 2013-05-26, Mischanko, Edward T <Edward.Mischanko at arcelormittal.com> wrote:
>> -----Original Message-----
>> From: questions-bounces+edward.mischanko=arcelormittal.com at lists.ntp.org
>> [mailto:questions-
>> bounces+edward.mischanko=arcelormittal.com at lists.ntp.org] On Behalf Of
>> unruh
>> Sent: Saturday, May 25, 2013 9:27 AM
>> To: questions at lists.ntp.org
>> Subject: Re: [ntp:questions] Tighter regulation?
>> 
>> On 2013-05-25, Mischanko, Edward T <Edward.Mischanko at arcelormittal.com>
>> wrote:
>> >
>> >> -----Original Message-----
>> >> From: Charles Swiger [mailto:cswiger at mac.com]
>> >> Sent: Friday, May 24, 2013 1:01 AM
>> >> To: Mischanko, Edward T
>> >> Cc: questions at lists.ntp.org
>> >> Subject: Re: [ntp:questions] Tighter regulation?
>> >>
>> >> On May 23, 2013, at 10:02 PM, "Mischanko, Edward T"
>> >> <Edward.Mischanko at arcelormittal.com> wrote:
>> >> > It takes too long to figure out it needs a more aggressive
>> correction.
>> >> > If I leave maxpoll at the default of 1024 seconds, my clock drifts
>> >> outside
>> >> > of 5 milliseconds consistently.
>> >>
>> > [Mischanko, Edward T]
>> >
>> > Measured by the best time sources I have available.  I am saying that my
>> 
> [Mischanko, Edward T] 
>
> What details do you want?  I am syncing to 10 stratum 4 servers in my case.
>   Servers outside of my LAN are blocked by the corporate firewall.
>
>> And maybe it is that "best" that is wrong. Why not give the details so
>> we can decide?
>> 
>> >  clock will drift to 5 milliseconds at maxpoll 10 and polling does not
>> >  decrease to a level that will bring my clock back to an offset of +/- 1
>> >  millisecond.
>> 
>> Note that on maxpoll 10, the clock will freerun for about 7000 sec
>> between disciplines. 5ms in 7000 sec is about 1PPM.
>
> [Mischanko, Edward T] 
>
> I don't believe the room temperature changes much at this computer's
>  location.

It is not the room temp. It is the computer temp. That is determined
almost entirely by what the computer is doing, not the room. Only if the
computer never does anything is the room important. 


>
> Now if your computer
>> heats up and cools down by 20C over an hour that could change the clock
>> by a few ms. And ntpd is slow to respond to changes in clock rate.
> [Mischanko, Edward T] 
>
> If I do maxpoll 8, then I get regulation within 1 millisecond.  What other
>  details would you like?  I can post my loopstats in the future if that
>  would be helpful?

The do maxpoll 8. "doctor -- my head hurts when I bang it against the
wall" "Well, stop banging it against the wall."


>
>> What happens if you do maxpoll 6? Give us details, not vague statements.
>> 
> [Mischanko, Edward T] 
>
> I do not know how to analyze the peerstats file, but I can post it if that
>  would help?

No. I do not particularly want to analyse your file. The important
columns are the time and the offset. -- col 2 (the time) and 5, the
offset. 
5
Plot offset vs time for each of the peers you use. 



>
>> Also try plotting peerstats and the offset as a function of time.
>> 



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