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Re: [gpsd-dev] [PATCH] Improve chrony examples in time howto.
From: |
Miroslav Lichvar |
Subject: |
Re: [gpsd-dev] [PATCH] Improve chrony examples in time howto. |
Date: |
Mon, 4 Nov 2013 16:30:00 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Mon, Nov 04, 2013 at 10:03:29AM -0500, Greg Troxel wrote:
> "Eric S. Raymond" <address@hidden> writes:
> > Miroslav Lichvar <address@hidden>:
> >> On Mon, Nov 04, 2013 at 07:18:16AM -0500, Greg Troxel wrote:
> >> > Miroslav Lichvar <address@hidden> writes:
> >> Please note that the performance of chronyd on non-Linux systems may
> >> not be adequate for the precision of the PPS source. Its system driver
> >> will use only the old adjtime() system call to discipline the clock,
> >> there is no correction of the frequency offset and the resolution is
> >> limited to microsecond.
> >
> > Ship another patch to this effect, please.
>
> And please be more measured about "adequate". The notion that there
> are sub-microsecond issues can be a bit hysterical on systems that don't
> have all other issues addressed.
Any suggestions on how to rephrase it? The problem is the uncorrected
frequency. The time error of the clock has a sawtooth profile with
amplitude proportional to the drift of the clock. If the drift is in
single digit ppm, perhaps the error may be acceptable, but I'm not
really sure.
> (I haven't gotten around to trying chrony yet.)
Please let us know if you do. I haven't tried it on NetBSD or heard
from another user for a very long time.
--
Miroslav Lichvar
Re: [gpsd-dev] [PATCH] Improve chrony examples in time howto., Gary E. Miller, 2013/11/04