| Re: [chrony-dev] [PATCH] MacOS X - Dynamic drift removal interval |
[ Thread Index |
Date Index
| More chrony.tuxfamily.org/chrony-dev Archives
]
On Tue, Aug 11, 2015 at 10:26:44PM +1200, Bryan Christianson wrote:
> 5 servers from each of the NZ and US pools - so combining is in effect. In looking at our NZ servers (about 10ms round trip over my DSL link) I am seeing about 1/2 the interval you suggest. If C1 (we need a better name) is increased from 0.1 to say 0.25 than update interval should be pretty close to the 5 - 10 sec range
>
> I have 3 servers on my LAN, including a stratum 1 USB GPS PPS that is good to about 5 usecs - and thats close to the 'System time' I'm seeing on the Mac.
>
> I think this approach works quite well and a bit of fine tuning on the constant should get a good compromise for typical use cases.
Ok. If no good compromise is found, there could be a "power saving"
option that would set the minimum allowed update interval.
BTW, when experimenting with multiple sources and longer drift removal
intervals I think it might be useful to rework the
get_offset_correction() function to not stop and restart the currently
running adjustment, but only read the remaining offset with
adjtime(NULL, &tv), so NTP measurements from sources other then the
selected peer are not restarting the drift removal. This would also
reduce the number of adjtime() calls, especially on a NTP server.
--
Miroslav Lichvar
--
To unsubscribe email chrony-dev-request@xxxxxxxxxxxxxxxxxxxx with "unsubscribe" in the subject.
For help email chrony-dev-request@xxxxxxxxxxxxxxxxxxxx with "help" in the subject.
Trouble? Email listmaster@xxxxxxxxxxxxxxxxxxxx.