Add more precise information on clock synchronisation

[ycongal-smile]

https://github.com/seapath/svtrace-ansible/blob/main/README.md?plain=1#L95:

Manually, using phc2sys to synchronize the SV network card with the PTP one

I feel like the above need more details.

To successfully run the test I've had to run

sudo phc2sys -c $SV_IFACE -s CLOCK_REALTIME -O 0 -mql6

I can't explain the -O 0. Network PHC should be in TAI so there should be a 37s offset from CLOCK_REALTIME which is UTC. I have not found where in svtrace the PHC of the receiving interface is used. Maybe I've missed something...

[Paullgk]

Hello Yoann,

• This parameter seems redundant as the default offset between the master and the slave is already set to 0 seconds. It can be safely removed.
• The -s CLOCK_REALTIME argument specifies that the PTP source used to synchronize the device (in your example, the clock of your SV network interface) should be the system clock. The system clock itself is synchronized by ptp4l using a valid PTP source.
• In our template examples, no conversion between TAI and UTC is required because we use a hardware PTP source that already sends time in UTC format.

PTP configuration heavily depends on the hardware setup. The files provided by svtrace-ansible are meant to serve as an implementation example and may require adjustments to fit different setups.

PTP configuration is very dependant of the hardware setup; The files provided by svtrace-ansible are more as an exemple of implementation, and could needs some adaptation to work on another setup. If you have troubles with PTP in eapath, I highly recommend you to checkout the Wiki page on this subject:

If you encounter any PTP-related issues in Seapath, I recommend checking out the Wiki page on this subject here: https://lf-energy.atlassian.net/wiki/spaces/SEAP/pages/31820633/Time+synchronization