CPU temp reporting

[Dimi3]

Hello,

Im testing new Intel N200 box, and came across interesting issue with CPU temperature reporting. My fanless box is practically cool to touch, but CPU temp in OPNSense is reporting 45 degrees, that it seemd to me too much. So I did some digging.

If I log in console and issue, I got more realistic CPU temp with command;

sysctl dev.cpu | grep temperature
dev.cpu.3.temperature: 35.0C
dev.cpu.2.temperature: 35.0C
dev.cpu.1.temperature: 36.0C
dev.cpu.0.temperature: 35.0C

I checked what command is OPNSense using for temp sensors and its;

sysctl -a | grep temperature
hw.acpi.thermal.tz0.temperature: 27.9C
dev.cpu.3.temperature: 45.0C
dev.cpu.2.temperature: 45.0C
dev.cpu.1.temperature: 44.0C
dev.cpu.0.temperature: 43.0C

If I stress test the machine this 2 temps come together at 55 degrees after 30 min witch is ok.

I installed HTOP and check the temp there, the lower values are reported, with occasional spike above 40 but average at 36 - 37 degrees.

I live booted linux on the same machine and checked linux temp sensors .. they are also reporting average of 36 - 38 degrees.

Out of curiosity I also spin up pfsense, and temp was also ok .. no spikes above 40 degrees. - but pfsense is using different command to read cpu temp then opnsense.

Overall this is not life threatening situation 😊 😊, but only my observation I decided to post it here. According to my testing both temps are correct higher temp is actually achieved by CPU when short load hits it, but it lasts less then a second and it falls to 36 degrees. It looks to me that the command sysctl -a | grep temperature is displaying max values in certain period, averaging in higher temp in dashboard that it really is.


I also tested this on my other firewall running Intel core I5 and there the difference is max 2-3 degrees Celsius, that its not really noticeable.

I also searched the forum, and few similar post have already been posted;

https://forum.opnsense.org/index.php?topic=34395.msg166556#msg166556

I think that it would be good to revise the temp monitoring and maybe use sysctl dev.cpu | grep temperature as it reports more "real" CPU temp.

Regards,

[vicking]

Bumping this old thread because I see the same behavior!