William Unruh <un...@invalid.ca> wrote: > On 2015-02-19, Rob <nom...@example.com> wrote: >> Miroslav Lichvar <mlich...@redhat.com> wrote: >>> On Thu, Feb 19, 2015 at 10:05:45AM +0000, Rob wrote: >>>> We have systems in places that are not temperature controlled and then >>>> chrony is much better. I am looking for the best way to find the >>>> values to use in the tempcomp configuration directive. >>> >>> What resolution does the sensor have? Don't expect good results >>> with 1C or 0.5C resolution that sensors on mainboards typically have. >> >> I am still finding out what sensor is best to use, we do have a room >> temperature sensor that has .1C resolution and is readable via snmp, >> and there are the usual sensors for board- and inlet air temperature. >> (and of course CPU temperature) >> >> It does not matter if it is only a course indication, the room temperature >> varies over a -10 .. 50C range (don't ask...) and a 1C resolution is not >> bad relative to that. > > It is of course the temperature of the crystal itself that is important. > Ie, the room temp could be constant and the computer varies in its > workload and thus its internal temperature. Unfortunately temp sensors > on the crystal are rare in commodity computers.
I am not looking for a precise crystal temperature but for a ballpark value that will compensate for the quick temperature swings that occur when this system (which is in an unheated glasshouse) quickly warms up when the sun rises, and cools down when the sun sets. In ntpd these events result in offset swings that are the derivative of the temperature. In chrony the swings are smaller, but it may be deceptive because I have not yet found a completely satisfactory way of gathering an "average offset" that is similar to the offset value in ntpq -c rv. _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
