On 2015-02-21 01:00, Rob wrote:
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.
Hi Rob,
If the systems can run x86/x64 Linux with Mono and WinForms or Windows
with .NET 2+ then OpenHardwareMonitor may be able to log the system
sensors.
For Linux see if lm_sensors/sensord/sensors/sensors-detect are available
on or for your system and look for data in:
/proc/acpi/thermal_zone/
/sys/bus/platform/devices/*temp*/
/sys/class/hwmon/hwmon[0-9]*/
/sys/class/thermal/{thermal_zone,cooling_device}[0-9]*/
Once you have the data, you may want to try weighted or windowed incremental
RMS values of temperature and frequency drift to see if they can be correlated.
--
Take care. Thanks, Brian Inglis
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