From mboxrd@z Thu Jan  1 00:00:00 1970
From: Richard Cochran <richardcochran@gmail.com>
Subject: Re: [PATCH net-next v2 1/8] net-timestamp: explicit SO_TIMESTAMPING
 ancillary data struct
Date: Tue, 8 Jul 2014 08:08:18 +0200
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Cc: Willem de Bruijn <willemb@google.com>, netdev@vger.kernel.org,
	David Miller <davem@davemloft.net>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Stephen Hemminger <stephen@networkplumber.org>,
	Chad Reese <kreese@caviumnetworks.com>,
	David Daney <david.daney@cavium.com>
To: Chad Reese <kreese@cavium.com>
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On Tue, Jul 08, 2014 at 07:49:19AM +0200, Richard Cochran wrote:
> On Mon, Jul 07, 2014 at 02:08:57PM -0700, Chad Reese wrote:
> > 
> > No, it was 1ns. Who would go through all this effort if all you
> > wanted was 1us?  Our requirement was within 20ns, but me managed to
> > get 1ns with a lab setup. We had to be careful that the scope probes
> > used in the measurement were the same length.
> 
> Well, in a lab, carefully compensating for phy delays, etc, etc,
> achieving 1ns is one thing. As a general statement, telling the
> public, "our PTP hardware synchronizes to within one nanosecond",
> is quite another thing.

And you are using synchronous Ethernet, too, I suppose?

Thanks,
Richard