Hi Richard and Jacob,

The most interesting is that on RHEL7 the 36 second offset occurs after the 
tx_timestamp_timeout error and after that the offset only drifts further away. 
(After staying ‘synchronised’ in the 36xxxxxxxxx range for a little of time)

I had tried the exact same thing between two HP Z440 PC’s (including the exact 
same Ethernet adapter + driver) running Ubuntu (instead of RHEL7). The 
tx_timestamp_timeout erorr occurred also on this slave server when pushing an 
.iso of +-5GB over the Ethernet line, except it didn’t got an offset of 36 
seconds, and it even re-synchronised after a while, while the RHEL7 slave only 
drifts further away when pushing a lot of network traffic from that PTP slave 
server over the network.

Jord

On 10 Aug 2018, at 17:11, Keller, Jacob E <jacob.e.kel...@intel.com> wrote:

>> -----Original Message-----
>> From: Richard Cochran [mailto:richardcoch...@gmail.com]
>> Sent: Thursday, August 09, 2018 6:16 PM
>> To: Keller, Jacob E <jacob.e.kel...@intel.com>
>> Cc: Jord Pool <jord.p...@outlook.com>; Cliff Spradlin via Linuxptp-users
>> <linuxptp-users@lists.sourceforge.net>; Chris Caudle <ch...@chriscaudle.org>;
>> Cliff Spradlin <csprad...@waymo.com>
>> Subject: Re: Fixing offset jump at reset?
>> 
>>> On Thu, Aug 09, 2018 at 07:10:44PM +0000, Keller, Jacob E wrote:
>>> Would it make more sense to have some "timecounter_reset()" function,
>> which uses the current nsec value and just resets the internal cycles? Then, 
>> as
>> long as the timecounter was updated as close as possible to before the 
>> hardware
>> reset, we'd only lose a few cycles, instead of getting the UTC/TAI 
>> conversion.
>> 
>> I guess it makes some kind of sense.  BUT still the new time will be
>> wrong.  And now it will be subtly wrong.  Maybe that would be even
>> more harmful, because it degrades the time quality while papering over
>> the driver/HW issues.
>> 
>> Thanks,
>> Richard
> 
> I'm just thinking in terms of the fact that if a reset occurs, that hardware 
> will simply have the wrong time now. It's faster for ptp4l to recover from a 
> small offset, than it is for it to recover from a 36second offset.
> 
> Hmm.. I suppose one could argue "why is it resetting in the first place" 
> though. Perhaps the driver is being overly aggressive about the reset, or 
> "resetting" ptp functionality even when it didn't have a proper hardware 
> reset.
> 
> Thanks,
> Jake
> 
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