Re: [chrony-users] Re: Locking PPS refclock with NTP source

[Thibaut BEYLER <thibautbeyler@xxxxxxxxx>]

No I tested it on ordinary x64 kernel (4.9 , 3.16 etc..) coming from debian & fc repos with no custom options.

I just installed pps-linux and invoked 'ldattach 18 /dev/ttyS0' (which also loads pps_ldisc module) , maybe i'm missing something ?

2017-08-30 18:51 GMT+02:00 Miroslav Lichvar <mlichvar@xxxxxxxxxx>:

On Tue, Aug 29, 2017 at 04:58:14PM +0200, Thibaut BEYLER wrote:
> > #* PPS0                              0   4   377    11  +4829ns[+6161ns]
> >> +/- 3021ns

> > PPS0                               23  17   383     +0.001        0.052
> >>          +5ns    5548ns

> I am using pps_ldisc, i tried pps-gpio but it was not better.
>
> I am using a custom serial cable (pin 1 of the serial cable is linked to
> the bnc ouput on the gps timeserver), same setup had given good results
> using an other software.

The chronyc output suggests the PPS input is very jittery. What
architecture is that? If it has GPIO I'd assume it's not just an
ordinary x86_64 computer. Also, what kernel version is it running? Is
the NOHZ config option enabled? Disabling it with nohz=off might help.

--
Miroslav Lichvar

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