[ntp:questions] ntpd wedged again

Dave Hart hart at ntp.org
Sat Feb 11 14:51:33 UTC 2012


On Sat, Feb 11, 2012 at 09:21, A C <agcarver+ntp at acarver.net> wrote:
> So ntpd has been behaving reasonably well with the snprintf fix.  I had good
> results with only internet servers.  My PPS and SHM refclocks were set to
> noselect.
>
> I removed the noselect on the PPS refclock and left flag3 set to zero (no
> kernel discipline).
>
> Everything seemed fine and then:
>
>> Sat Feb 11 01:12:10 PST 2012
>>     remote           refid      st t when poll reach   delay   offset
>>  jitter
>>
>> ==============================================================================
>> x127.127.22.0    .PPS.            0 l    -   16  377    0.000  -111.40
>> 351.464
>>  127.127.28.0    .GPSD.           4 l   49  128  377    0.000  -14655.
>> 2814.64
>>  169.229.70.201  169.229.128.214  3 u  103  512  377   39.347  -9274.2
>> 6597.61
>>  72.14.179.211   127.67.113.92 2 u   79  512  377   57.746  -14699.
>> 10685.0
>>  24.124.0.251    132.236.56.250   3 u  521  512  377   77.930  -9835.0
>> 7451.10
>>  130.207.165.28  130.207.244.240  2 u  153  512  377   79.131  -9155.6
>> 6554.15
>>  131.144.4.10    130.207.244.240  2 u  142  512  377   86.537  -9102.3
>> 6526.3

Did you forget to mention you commented out the NMEA refclock at the
same time you removed noselect from the atom/PPS and SHM drivers?

I am a bit tired right now, so forgive me for latching onto a nit
rather than the juicy part, but I want to be as clear as possible.
You say everything was fine until you made some changes, without
specifying the previous state, and when I try to infer what that
earlier state was based on the two changes, I'm left with a setup with
no refclocks, which is obviously not particularly comparable.  I'm
also hesitating to point a finger at the gpsd+SHM combo, particularly
because I suspect it's racy especially on non-x86 systems and have on
my to-do list rewriting it to use a safer shared memory access
protocol...

So first, let's be clear about what you're reporting.  Was the change
from 3 refclock drivers with 2 marked noselect to 2 selectable
drivers?

Cheers,
Dave Hart

Cheers,
Dave Hart


More information about the questions mailing list