Hi,
I want to sync my PHC clock with system clock as the source, so I executed the
command:
ptp4l -i ens2f1np1 -m
phc2sys -a -r -r -m
The phc2sys seems running correctly:
$phc2sys -a -r -r -m
phc2sys[7362514.851]: reconfiguring after port state change
phc2sys[7362514.851]: selecting ens2f1np1 for synchronization
phc2sys[7362514.851]: selecting CLOCK_REALTIME as the master clock
phc2sys[7362514.851]: ens2f1np1 sys offset -149 s0
freq -6182 delay 385
phc2sys[7362515.851]: ens2f1np1 sys offset -152 s2
freq -6185 delay 382
phc2sys[7362516.851]: ens2f1np1 sys offset -143 s2
freq -6328 delay 380
However, it creates a stable offset between the phc clock and the system
clock,
which is about -37000000011ns:
$phc_ctl ens2f1np1 cmp
phc_ctl[7362590.195]: offset from CLOCK_REALTIME is -37000000001ns
$phc_ctl ens2f1np1 cmp
phc_ctl[7362590.688]: offset from CLOCK_REALTIME is -37000000004ns
$phc_ctl ens2f1np1 cmp
phc_ctl[7362591.107]: offset from CLOCK_REALTIME is -37000000002ns
$phc_ctl ens2f1np1 cmp
phc_ctl[7362591.476]: offset from CLOCK_REALTIME is -36999999999ns
I'm wondering why the offset exists. The purpose for I want to do this
sync is because the phc clock has a linear delay than the system clock, and I
need to
have an accuracy phc clock for the packet hardware timestamping. I'm not
familiar with
the nic hardware clock, don't know if it's normal.
My OS is RedHat 8.6 with 4.18.0-372.9.1.el8.x86_64. The phc2sys and
ptp4l
version are 3.1.1.
Thanks a lot.
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