Re: [chrony-users] PHC / NIC / PPS mismatch

[Christopher Hoover <ch@xxxxxxxxxxxxxx>]

p.s. in all cases ntpshmon shows data:

christopher@apu-42:~$ sudo ntpshmmon
ntpshmmon: version 3.22
#      Name  Seen@                 Clock                 Real                 L Prc
sample NTP0  1637034947.292044404  1637034947.090644472  1637034947.000278692 0 -20
sample NTP0  1637034948.110421061  1637034948.109557612  1637034948.000278696 0 -20

(this is the deb 11 box that doesn't see PPS on the NIC at all.)

-- Christopher.

On Mon, Nov 15, 2021 at 7:44 PM Christopher Hoover <ch@xxxxxxxxxxxxxx> wrote:

I upgraded the 4-nic box to Debian 11.

kernel 5.10.0-9-amd64 #1 SMP Debian 5.10.70-1

chrony 4.0-8

Using same config file that work under Debian 10, startup fails because of the comma in

---
refclock PHC /dev/ptp3:extpps,pin=0 refid PPS width 100e-3 precision 1e-9 poll 0 lock NMEA trust

---

Changing the comma do colon does not work (reflock PPS sees nothing).

I dropped the "lock NMEA trust":

---

refclock PHC /dev/ptp3:extpps refid PPS width 100e-3 precision 1e-9 poll 0

---

no pin does not work (reflock PPS sees nothing)

:pin=0 does not work (reflock PPS sees nothing)

:pin=1 does not work (reflock PPS sees nothing)

I suppose I can reinstall Debian 10 and roll the kernel to 5.x with backports.

-- Christopher

On Mon, Nov 15, 2021 at 6:31 PM Christopher Hoover <ch@xxxxxxxxxxxxxx> wrote:

This works on the 4 NIC board:

---
refclock PHC /dev/ptp3:extpps,pin=0 refid PPS width 100e-3 precision 1e-9 poll 0 lock NMEA trust

---

but without ",pin=0", it does not.

On nearly identical hardware, difference being  3 NICs ( PPS wired to the 'last' NIC in both cases),  this works fine:

---

refclock PHC /dev/ptp2:extpps refid PPS width 100e-3 precision 1e-9 poll 0 lock NMEA trust

---

Same kernel (4.19.0-18-amd64 #1 SMP Debian 4.19.208-1).     Same chrony (3.4-4+deb10u1).

I'll roll the kernel forward and chrony forward from Debian 10 to Debian 11 and report results.

-- Christopher.

On Mon, Nov 15, 2021 at 12:54 AM Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:

On Fri, Nov 12, 2021 at 05:28:56PM -0800, Christopher Hoover wrote:
> refclock SHM 0 refid NMEA precision 1e-3 poll 3 offset 100e-3 noselect
> refclock PHC /dev/ptp2:extpps refid PPS width 100e-3 precision 1e-9 lock
> NMEA poll 0 trust

> If I look for PPS, I find it on ptp0/pps0 with Bullseye.

> It is not found anywhere else.
>
> If tried telling chrony to /dev/ptp0 instead of /dev/ptp2, but it does NOT
> find the PPS.

Does the SHM refclock work correctly? If it didn't, the PPS PHC
wouldn't report any samples. You could try removing the lock option
and add an NTP server to be sure.

I don't remember any changes between chrony-3.4 and 4.0 that could
have an impact in this configuration.

You could try adding ":pin=1" to the PHC refclock config, to see if
the newer kernel is numbering the pins differently, but I doubt it.

If that doesn't help, run chronyd in strace for few seconds and post
the output here.

--
Miroslav Lichvar


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