Re: [Linuxptp-users] Need help debugging failed clock synchronization

[Keller, J. E <jac...@in...>]

Hi John,

On Wed, 2016-03-16 at 13:45 -0700, John Hubbard wrote:
> On 03/16/2016 12:54 PM, Richard Cochran wrote:
> > 
> > On Wed, Mar 16, 2016 at 10:20:35AM -0700, John Hubbard wrote:
> > > 
> > > After changing the 'time_stamping' option in /etc/ptp4l.conf from
> > > hardware to software and restarting ptp4l I now see much better
> > > behavior.
> > Yes, but probably you are disappointed having to forego the HW
> > synchronization performance.  At least this test shows that your
> > card
> > most likely has a HW bug.
> If possible it would be really nice to get the HW time-stamping
> working 
> on this system.  I can move to another system if needed but getting
> this 
> working would help me in the short term.  (No expansion ports or I'd 
> just pick up another NIC.  On a related note do you or anyone else
> on 
> the list know how well the Intel X540 (10Gb NIC using the ixgbe
> driver) 
> is supported WRT ptp4l?
> 

The X540 device should be supported WRT ptp4l, and as far as I know it
works quite well. I am sorry for the troubles the e1000e adapter is
causing. It is most likely a driver issue. I am not 100% sure who is
responsible for that driver now, but I will attempt to determine if the
latest errata have been released on SourceForge yet. (It can be slow
sometimes)

> > 
> > > 
> > > I believe that I did try the Intel driver but didn't see any
> > > success.  I
> > > found version 3.3.3 of the driver at [3], followed the
> > > instructions in
> > > the readme.  At the time I was running the 3.10.0-327.10.1
> > > kernel.  The
> > > timestamp (see below) on e1000e.ko matches up with when I
> > > performed the
> > > build, and the file size is way bigger (6M as compared to ~780K)
> > > for the
> > > ko on the older 3.10 and the newer 4.5 kernels.  I did an rmmod
> > > (which
> > > hung my SSH session) I then rebooted the machine (which I assume
> > > loaded
> > > the new driver).
> > I wouldn't assume that.  Either do rmmod/insmod by hand (on the
> > console!) or simply rename or move the original driver before
> > rebooting.
> OK the machine has got three kernels installed.  Here's the e1000e 
> driver version (as reported by modinfo) for each:
> 
> Kernel 3.10.0-327 e1000e version 3.2.5-k
> Kernel 3.10.0-327.10.1 e1000e version 3.3.3-NAPI
> Kernel 4.5.0-1 e1000e version 3.2.6-k
> 
> Under all three kernels with software time stamping things 'work'
> but 
> with more jitter than I'd like to see.  With hardware time stamping 
> things don't work.  Specifically I see clock jumped forward messages
> and 
> an ever increasing master offset.
> 
> 

As Richard suggested, I would use testphc program to debug if you have
a weird driver issue or not.

It is very likely an issue with the hardware for this part, as there
are several errata regarding the SYSTIME clock as Richard noted
earlier.

Regards,
Jake