hello Jake,
Did time profiling using time ticks. Under the problem condition, observing 
clock_gettime of interface connected to BC is taking more time ticks. This 
results in phc offset jumping to 4 digit value momentarily. Also i'm not sure 
if reading across numa is triggering this issue.
Please suggest a way to fix in the phc2sys offset code?1) Should we prevent 
update on phc2sys value if there is momentarily jump?
Please suggest.
Thanks for your support on this issue.
Regards,Ramesh     On Thursday, April 29, 2021, 07:33:49 AM GMT+5:30, ramesh t 
via Linuxptp-users <linuxptp-us...@lists.sourceforge.net> 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 localNIC 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
    On Thursday, April 29, 2021, 04:05:34 AM GMT+5:30, Jacob Keller 
<jacob.e.kel...@intel.com> wrote:  
 
 

On 4/28/2021 12:01 AM, ramesh t via Linuxptp-users wrote:
> hi,
> 
> In our system, we have 3-4 ptp4l services running as master (C1 mode)
> providing clock to external device. Our system is synced using ptp
> support/slave connected to a BC. From the synced slave/support
> interface, phc2sys is used to sync master interface. All the master and
> slave ptp4l and phc2sys are core pinned. Once in a while phc offset
> which is synced into master interface using phc2sys jumps into 4 digit
> value. Any suggestion on how to debug this further.
> 
> Apr 28 03:26:51 k8s-worker-0 phc2sys: [131370.261] enp104s0f1 phc
> offset         4 s2 freq  -11419 delay   3610
> Apr 28 03:26:52 k8s-worker-0 phc2sys: [131371.261] enp104s0f1 phc
> offset         3 s2 freq  -11418 delay   3603
> Apr 28 03:26:53 k8s-worker-0 phc2sys: [131372.261] enp104s0f1 phc
> offset         3 s2 freq  -11417 delay   3568
> *Apr 28 03:26:54 k8s-worker-0 phc2sys: [131373.262] enp104s0f1 phc
> offset     -4973 s2 freq  -16393 delay  19341*
> *Apr 28 03:26:55 k8s-worker-0 phc2sys: [131374.262] enp104s0f1 phc
> offset      4977 s2 freq   -7934 delay   3594*
> *Apr 28 03:26:56 k8s-worker-0 phc2sys: [131375.262] enp104s0f1 phc
> offset      1471 s2 freq   -9947 delay   3591*
> Apr 28 03:26:57 k8s-worker-0 phc2sys: [131376.262] enp104s0f1 phc
> offset         0 s2 freq  -10977 delay   3587
> Apr 28 03:26:58 k8s-worker-0 phc2sys: [131377.262] enp104s0f1 phc
> offset      -449 s2 freq  -11426 delay   3596
> 

Ok

> After a while, we are observing NIC interface going down also.
> 
> Apr 28 03:28:22 k8s-worker-0 phc2sys: [131461.271] enp104s0f1 phc
> offset         5 s2 freq  -11421 delay   3559
> Apr 28 03:28:23 k8s-worker-0 kernel: i40e 0000:68:00.1 enp104s0f1: NIC
> Link is Down
> Apr 28 03:28:23 k8s-worker-0 kernel: br0: port 4(enp104s0f1.1) entered
> disabled state
> 
> Please suggest.

This looks like the i40e driver. This hardware has a clock that is
derived from the link speed. For this reason, the clock increment value
has to change whenever link status changes. I suspect that when the link
goes down, the driver is re-programming the increment value which is why
you see the change in clock.

You'd need to figure out why the link is dropping. There isn't much that
can be done from a driver or ptp4l perspective here.

Thanks,
Jake

> 
> Regards,
> Ramesh
> 
> 
> _______________________________________________
> Linuxptp-users mailing list
> linuxptp-us...@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linuxptp-users
> 


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