[ntp:questions] ATOM falseticker with flag3 enabled

A C agcarver+ntp at acarver.net
Thu Mar 29 03:11:16 UTC 2012


On 3/28/2012 19:44, A C wrote:
> On 3/28/2012 19:32, Dave Hart wrote:
>> On Wed, Mar 28, 2012 at 05:34, A C<agcarver+ntp at acarver.net> wrote:
>>> On 3/27/2012 22:07, Dave Hart wrote:
>>>
>>>> I suspect you will see that when you've used flag3 1, ntpd has
>>>> reported time_pps_kcbind failing. I do see a potential bug in that
>>>> code, though. If you don't get any hits from the fgrep, try removing
>>>> line 1259 from ntp_refclock.c:
>>>> if (errno != EOPNOTSUPP) {
>>>> and its matching closing brace on line 1265:
>>>> }
>>>> Then recompile ntpd and see if it then reports time_pps_kcbind failure
>>>> with flag3 1.
>>>
>>>
>>> Nothing happened with the recompiled version, it still enabled kernel
>>> PPS
>>> with no complaints:
>>>
>>>
>>> 28 Mar 05:27:43 ntpd[353]: 0.0.0.0 c012 02 freq_set kernel -77.202 PPM
>>> 28 Mar 05:28:00 ntpd[353]: PPS(0) 8024 84 reachable
>>> 28 Mar 05:32:13 ntpd[353]: 0.0.0.0 061d 0d kern PPS enabled
>>
>>
>> Thanks for trying that. I'm still suspicious of the code above. It
>> raises the question of whether failed implementation of flag3 1 should
>> also cause the driver to not use PPSAPI at all, which I think is the
>> effect of the return 0.
>>
>> Getting back to what you're seeing, it appears to me to be a bug
>> (likely in ntpd) interacting with PPSAPI hardpps on NetBSD 5.1. I
>> presume without flag3 1, your PPS(0) reach never changed from 0? And
>> that adding flag3 1 changed it so it became 377 eventually?
>
>
> Actually no, without flag3 the reach still became 377. PPS is reachable
> regardless of flag3.


Let me be more explict.  If flag3 is not set and a peer is marked as 
prefer then PPS is reachable and becomes flagged wtih a 'o' tally code. 
  If flag3 IS set and no peers are marked as prefer, PPS is also 
reachable but it's consistently flagged with a 'x' tally code.  In both 
cases of flag3, PPS is reachable.

I know I've tried flag3 disabled but no peer marked prefer however I 
don't remember the result of that.

I'd love to understand why PPS is flagged the way it is in the above 
conditions.  In both cases PPS is being used to control the system clock 
but in the case of flag3 enabled, it's showing as a false ticker (but 
still being used).


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