On 8/14/13 12:31 AM, "Richard Cochran" <[email protected]> wrote:

>On Tue, Aug 13, 2013 at 09:36:25PM +0000, Vick, Matthew wrote:
>> 
>> For the occasional "hiccup" on the RJ45 side, if the 82576 tries to
>> timestamp two outbound packets too quickly, it will fail to return the
>> second one (since the hardware is busy timestamping the first one).
>> 
>> What options are you running with ptp4l? -P should help reduce the
>>number
>> of failed timestamps on the RJ45 port.
>
>I don't think changing ptp4l's options makes any difference. That
>program is single threaded, and it always waits for the time stamp
>after sending an event message. This behavior is quite on purpose,
>knowing that some of the hardware out there can only handle on at a
>time.
>
>On the linuxptp-users list, Alexander also recently reported frequent
>time stamp failures on peer delay request messages. It is beginning to
>look like the 82576 has a bug in this regard.
>
>Thoughts?
>
>Thanks,
>Richard

I believe changing options does make a difference for the 82576. At least,
I had issues with E2E in the past--I would need to re-test to confirm if
there is still an issue or not. I remember getting Rx packets to be
timestamped too close together, which the 82576 cannot support, but I did
grab the tip of the ptp4l tree and not a stable release at the time.

Adding Jake to the thread, since I'm fairly certain that Alexander was
using a modified driver or stack to do something non-standard, so it
wasn't a bug with the 82576. Jake, do you remember what the root cause was
on that one?

Cheers,
Matthew


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