| Re: [chrony-users] Commercial unit running chrony, benefits of 'xleave' ? |
[ Thread Index |
Date Index
| More chrony.tuxfamily.org/chrony-users Archives
]
- To: chrony-users@xxxxxxxxxxxxxxxxxxxx
- Subject: Re: [chrony-users] Commercial unit running chrony, benefits of 'xleave' ?
- From: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
- Date: Thu, 3 Feb 2022 15:04:07 +0100
- Authentication-results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=mlichvar@xxxxxxxxxx
- Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643897057; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Ta/NBH1vQPfke5ZivR7oThLE4nzDhn+8rEVANo6qLCI=; b=SYFXAOHtjoyjvkD7F7tNAbq5qJJTS2V9mUJBv5AhGdfphkKnJmN9ZAT7PoCdn6fmzDbQOx VoNyxzsX+aMpdNJqdjqSW53eailcD1zqhT9v4TjaUGfZZ0FHrNR2t6KmR2QBEaZWaBabcn ZaPWkyxUsDHcm79+icG95rHprd/UKrQ=
On Thu, Feb 03, 2022 at 07:09:27AM -0600, Matthew Eshleman wrote:
> For example, I acquired:
> https://timemachinescorp.com/product/gps-ntpptp-network-time-server-tm2000/
>
> which works fine so far, however on a local LAN we are showing about +/-
> 1.5 ms of estimated error.
What does chronyc ntpdata print for the server?
> Fundamentally, I'm curious how much benefit we would see if the NTP server
> supports the "xleave" option, and then I'm curious if there is a known NTP
> server, preferably small and portable, that uses chrony.
I don't know any. It is a business opportunity nobody tried to make
money on yet. :)
An appliance that I know works well is LeoNTP sold by Uputronics.
It doesn't use hardware timestamps, but it has an embedded NTP
implementation with timestamps accurate to few hundred nanoseconds,
without relying on the xleave mode. The main I issue I have with it is
that the firmware is not opensource, so you can't easily fix bugs.
There are few mostly minor issues I reported years ago, which are
still not fixed.
If you would prefer something DIY running chrony, a good option would
be the PC engines apus. They have onboard I211 NICs which support
hardware timestamping and a serial port, to which could be connected a
GPS receiver. There are pads on the board for the I211 SDPs which can
be used for highly-accurate PPS timestamping, but soldering wires to
those tiny pads might not be for everyone. See this great post from
Dan Drown:
https://blog.dan.drown.org/apu2-ntp-server-2/
A promising option seems to the Raspberry Pi CM4, which supports
hardware timestamping, but unfortunately there is no support in the
driver yet:
https://github.com/raspberrypi/linux/issues/4151
--
Miroslav Lichvar
--
To unsubscribe email chrony-users-request@xxxxxxxxxxxxxxxxxxxx
with "unsubscribe" in the subject.
For help email chrony-users-request@xxxxxxxxxxxxxxxxxxxx
with "help" in the subject.
Trouble? Email listmaster@xxxxxxxxxxxxxxxxxxxx.