[SOLVED] CPU temperature not varying in lm_sensors

Indyman · 03-09-2018, 03:03 PM

Hi and thank you for reading my first post! I have a Slackware box running kernel4.14.23-smp on a Gigabyte GA-G31-ESL2 board with Intel Core2Quad Q9500. I want to monitor the CPU temps and this is the CPU readout of sensors (after running sensors-detect):

coretemp-isa-0000
Adapter: ISA adapter
Core 0: +38.0°C (high = +74.0°C, crit = +100.0°C)
Core 1: +38.0°C (high = +74.0°C, crit = +100.0°C)
Core 2: +39.0°C (high = +74.0°C, crit = +100.0°C)
Core 3: +39.0°C (high = +74.0°C, crit = +100.0°C)

Problem is the temp values never change - they remain at fixed values of 38 or 39C, so it doesnt appear that real-time monitoring is occuring. The coretemp module is loaded. Where does sensors pull it's CPU temp monitoring data and why is it not changing over time? Thanks in advance for your responses!

Skaendo · 03-09-2018, 03:26 PM

Try:

Code:

$ watch sensors

Indyman · 03-10-2018, 10:35 PM

Quote:

Originally Posted by Skaendo

Try:

Code:

$ watch sensors

Hi Skaendo
Good idea - I monitored the output for about 20 minutes. I also have fan speed, GPU and motherboard temps monitored and all of those values changed during that time - the CPU did not.

orbea · 03-11-2018, 01:10 PM

If you start compiling something with a slackbuild it still doesn't change?

Skaendo · 03-11-2018, 01:20 PM

Quote:

Originally Posted by Indyman

Hi Skaendo
Good idea - I monitored the output for about 20 minutes. I also have fan speed, GPU and motherboard temps monitored and all of those values changed during that time - the CPU did not.

Maybe the temp is pretty stable on your CPU, at least until there is a major load on it?

I have a i3-2130 and the temp hardly ever changes and only slightly when even under heavy load.

Like orbea said, try putting a load on it like running a SlackBuild with -j8. While monitoring it with one terminal watching sensors and another with htop.

Indyman · 03-11-2018, 03:29 PM

Ok got the CPU temp to change - ran p7zip SlackBuild (takes about 10 minutes to compile) and all temps went up, including CPU to +47C. After the compile all temps returned to their initial values. So I guess the at-rest temp of this CPU is pretty stable which is why I wasnt seeing any change before. Thanks Skaendo and orbea for your suggestions - I'm going to mark this one as SOLVED.

enorbet · 03-11-2018, 05:03 PM

Quote:

Originally Posted by Skaendo

Maybe the temp is pretty stable on your CPU, at least until there is a major load on it?

I have a i3-2130 and the temp hardly ever changes and only slightly when even under heavy load.

Actually that has to be an illusion, usually created by insufficient contact between sensors and the CPU core. If you can imagine the sizes and distances involved monitoring CPU temps is at best akin to towing a full-sized RV behind a Volkswagon and having the engine thermal sensor, weighing about a ton, located in the very back of the RV. The actual sources of thermals in a CPU are microscopic and very distant from any sensor. It's actually a wonder they work at all but then they only need be an approximation to be moderately useful.