CPU temperature monitoring (intel i7)

[Chopstick]

Hi,
I'm running jaunty and I have an intel i7 CPU; I'm using lm-sensors to monitor the temperature (had to build from source; the repository version did not work). Idle temperature is around 50C and load is about 70-75C. Apparently that is normal for i7 (according to some web posts). lm-sensors indicates "high" for 80C+ and "critical" for 100C+ - I'm far from that. I'm just using the stock cooler with no special equipment.
Do you observe similar values?

Here is my main question: lm-sensors indicates 8 different core temperatures, but the i7 only has 4 cores! (albeit 8 threads) In idle mode there are always pairs of identical numbers (4 pairs), but under load the temperatures fluctuate quite a lot, and the pairs are not identical anymore.

My interpretation is that lm-sensor queries temperatures twice for each of the for cores (because it thinks there should be 8?) and because of the fluctuation at high load levels, temperatures change between two queries to the same core...

Anyone any thoughts on this?
What are you guy using to monitor core temperatures in kubuntu (jaunty)? Would you recommend using a different monitoring software? I just started with this whole monitoring business...

[josefko]

Re: CPU temperature monitoring (intel i7)

There is a widget "System Monitor Temperature" in Add Widgets. On some notebooks it works out of the box. Maybe it's worth trying. My temperature with it is max 52C. I know nothing more about it.

[Chopstick]

Re: CPU temperature monitoring (intel i7)

I'm also using this widget for display, but as I understand, it relies on lm-sensors. At least the widget only started working after I installed lm-sensors properly...

Neither on my laptop nor on my desktop PC did it work "out of the box".

On my laptop, both lm-sensor (command line) and the widget correctly display two cores. But on my desktop PC (the i7) both indicate 8 cores, with the behavior described above.

So do you also have an i7, Josefko? I read that i7's generally run at higher temperature than core 2's.

[josefko]

Re: CPU temperature monitoring (intel i7)

In the Temperature widget settings there is a sensor described as:

acpi/thermal_zone/THM/temperature

It is possible to read the temperature using shell:

$ cat /proc/acpi/thermal_zone/THM/temperature

I don't know, where the sensor is located, but there is only one temperature.
My processor is Intel Core 2 Duo CPU T7250 2 GHz
The temperature right after start is 32C.
I didn't test it under heavy load, just Internet and so on, maybe it is what you named idle.

[Chopstick]

Re: CPU temperature monitoring (intel i7)

OK, the widget I'm using is called "System Monitor - Temperature". The Sensor indicated in the settings menu is 'lmsensors/coretemp-isa000x/temp1' where the 'x' is a number ranging from 0 to 7 (i.e. 8 sensors).

Are you using a different widget? Mine is part of the "System Monitor" components in KDE 4.2.4.

The folder you describe, Josefko, is empty on my system...

My laptop also has a Core 2 Duo CPU and usually shows values similar to yours. (Although measured by lmsensors...)

[josefko]

Re: CPU temperature monitoring (intel i7)

It is the same widget. I think it is only a frontend and during installation looks around which sensors are available. If you installed lmsensors so it finds them.
I don't remember installing something for temperature measurement. I looked now at my netbook and there is a similar dictionary, instead of THM called THRM, there is a file with temperature in it, but unfortunately with a bad, constant value 27C. So I really do not know how it works.
There are others which have this dictionary with something, I tried to google "thermal_zone/THM" and found for example this http://ubuntuforums.org/showthread.php?t=87538