On 4/28/2021 7:00 PM, ramesh t wrote:
> hi Jake,
>
>> enp104s0f1 phc offset 3 s2 freq -11417 delay 3568
>> enp104s0f1 phc offset -4973 s2 freq -16393 delay 19341* <<<<<<<HERE
>> enp104s0f1 phc offset 4977 s2 freq -7934 delay 3594*
>> enp104s0f1 phc offset 1471 s2 freq -9947 delay 3591*
>> enp104s0f1 phc offset 0 s2 freq -10977 delay 3587
>
> Main issue in hand is why there is change in delay which resulted in
> jump of phc offset? which recovers back?
> Is there any mechanism to avoid such drifts the phc?
>
> From the ptp4l code, below code is used for calculating delay
>
> if (clock_gettime(sysclk, &tdst1) || <<< Read of local
> nic time
> clock_gettime(clkid, &tsrc) || <<< Read
> of remote nic time (interface connected to BC)
> clock_gettime(sysclk, &tdst2)) { <<<
> Read of local nic time
> pr_err("failed to read clock: %m");
> return 0;
> }
> Then we calculate the interval between two reads of local NIC with below
> code:
>
> interval = (tdst2.tv_sec - tdst1.tv_sec) * NS_PER_SEC + tdst2.tv_nsec -
> tdst1.tv_nsec;
> This interval maps to delay.
>
> Please suggest.
>
> Regards,
> Ramesh
>
Delay is a measurement of how long packets take to traverse the network.
This could be changing due to some network issue.
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