Re: [chrony-users] Possible to get sub-millisecond accuracy?

[Chris Perl <cperl@xxxxxxxxxxxxxx>]

On Fri, Jun 9, 2017 at 3:29 AM, Miroslav Lichvar <mlichvar@xxxxxxxxxx> wrote:

Note that in 7.4 will be chrony-3.1, which supports HW timestamping.
If you don't have switches with PTP support and the NIC on the machine
can timestamp all packets (not just PTP packets), NTP might work
better for you.

Sorry for taking a slight aside here.  Does that also mean that 7.4 is going to ship with the necessary kernel changes backported to allow hardware timestamping to work?

I have played around with chrony 3.1 on both CentOS 6.8 and CentOS 7.3 (built myself) and both were missing kernel features necessary to allow the hardware timestamping to work (I believe in 6 it was lack of `SO_SELECT_ERR_QUEUE' and `SOF_TIMESTAMPING_OPT_CMSG', but in 7 it was just the latter).