[lm-sensors] Preferred way to obtain thermal data on Linux?

armencho at gmail.com armencho at gmail.com
Sun Feb 22 15:25:22 CET 2009


I have a Thinkpad T61. Reading from /proc/acpi/ibm/thermal works fine
but generates too many interrupts - reading the file once per 5
seconds generates 20 interrupts waking up the CPU, wasting battery
life and outputting extra heat very strictly speaking, although many
would not care. Admittedly reading sensor data through
/sys/class/hwmon/*/device/*_input files ALSO interrupts the CPU,
albeit not so often. The /proc interface is also deprecated they say.
In light of the latter, the multitude of ways to obtain readings, and
the fact that I am trying to find battery-life optimal way to read the
sensors continually (most hardware monitors do so), i was wondering:

What interface is most reliable, generic and least resource intensive
for obtaining sensor readings in Linux (2.6.27.11)?

The reason I am asking is that it seems both documentation of
thinkpad-acpi and libsensors mentions similiar facts, and touches the
same subjects, almost hinting that the development of these two
modules shares a lot of knowledge. Both have their own separate ways
to obtain sensor readings, and both prefer this or that. Also, I have
no knowledge of internal workings of libsensors, and whether it in
fact USES thinkpad-acpi or generic acpi driver or something else to do
its job. I just want to get a piece of advice concerning the best
method, and also one that is reliable. I know thinkpad-acpi gets data
per ACPI specs, and that libsensors does chip-specific stuff, but
still that does not give me confidence using either over the other...

-amn.




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