SoC temperature accuracy

[willmore]

I have an Orange Pi One Plus with the H6 chip in it and I'm quite happy with how well it's supported by Armbian.  I haven't really had any problems with it.

 

I do have one question, though.  I'm using armbianmonitor to "-m" monitor the machine and I notice that the temps are always pretty hot.  Even at idle (480MHz) it still shows 72C.  That seems higher than I would have expected.  Is this normal, expected behavior?  I understand that the SoC thermal monitoring code in the kernel is pretty new and therefore might not be perfect, yet.  So, I thought I'd ask.  Because it may just be my board that's off.

 

Does anyone know if this is normal?

Info:

The board is in a lightly vented case and there is no HS on the SoC.  There is light cross airflow in the area.

Armbian version is "Welcome to Debian Buster with Armbian Linux 5.3.0-sunxi64" with current software updates.

If there is more information I can provide, I would be glad to report it.  Thank you for your time.

[Igor]

8 hours ago, willmore said:

If there is more information I can provide, I would be glad to report it. 

This is mandatory when reporting strange things or bugs:

armbianmonitor -u

But I do not have an answer. It has to be investigated ...

[willmore]

Here you go, sir. armbianmonitor -u output

 

[NicoD]

20 hours ago, willmore said:

Does anyone know if this is normal?

Info:

The board is in a lightly vented case and there is no HS on the SoC.  There is light cross airflow in the area.

Armbian version is "Welcome to Debian Buster with Armbian Linux 5.3.0-sunxi64" with current software updates.

If there is more information I can provide, I would be glad to report it.  Thank you for your time.

Hi. I don't have the OPi1+, but I do have the OPi3 and PineH64.
Here are my temperatures for the OPi3

Temperature
-----------
With 5V fan idle : 35°C
+ heatsink maxed : 65°C  
3.3V idle        : 39°C
3.3V maxed       : 69°C			 
No fan/heatsink  : 55°C
     maxed       : between 73°C and 85°C throttle to 1.3Ghz over 75°C

Mine seem lower than what you are perceiving. But what's shown here is within seconds.
You could try with a fresh reboot, and wait a while for it to go to it's idle temp and check manually.

cat /sys/class/thermal/thermal_zone0/temp

You could also try to run SBC-Bench from @tkaiser
It takes a long time, but afterwards you get a good picture of the temperatures it's running at.(and many more...)

wget https://raw.githubusercontent.com/ThomasKaiser/sbc-bench/master/sbc-bench.sh
sudo /bin/bash ./sbc-bench.sh -c

https://github.com/ThomasKaiser/sbc-bench

My conclusion with the H6 was to use it at 1.5Ghz when you don't use a heatsink/fan. That way it doesn't overheat/throttle too quickly. In some CPU intensive tasks it will perform better because of this.

 

[megi]

This is a known bug in the THS driver. Fix is:

https://megous.com/git/linux/commit/?h=ths-5.3&id=555de6dfd8d7473d37e07047cb576accb620f896

[megi]

There are other issues too (interrupt frequency being too high for example). All the ths patches in my ths-5.3 tree are probably the latest and the most debugged code for thermal sensors on H6 and other soc atm, since the last version (v5) was posted to mailing list by Yangtao Li.

[SchmuseTigger]

So the temp shown after booting is not correct? Because mine still shows really high temps after booting without the pi doing anything basically. 

[megi]

Try to cool the board with a fan, if the temp will not change reasonably (by at least 15°C) the readings are incorrect.

You can also try running a CPU load test, but that can be unsafe if CPU temp is not being measured correctly. (it should rise considerably above 80 quite quickly)

 

The bug I'm talking about manifests by unreasonably small measured temperature changes (2-5°C) in reaction to load/cooling changes.

[SchmuseTigger]

Ah ok. I have a small fan, but I got a cheap one from china and it startet to make noise after a few weeks. I think I have to get some better ones. But my temp was about 10 degrees lower a few patches ago

[willmore]

My temp responds very well to added cooling.  I placed the boxed SBC next to a small fan and the temperature dropped by 20C.  So it may just be a board specific cooling issue.  I'll look into adding a heatsink and find a better source of improved airflow.

 

Thanks, megi, and Igor!

[megi]

@willmore Yeah, I think Armbian maybe still uses my THS patches, which contain the fix. Icenowy's H6 THS driver also has it right. So this is only an issue with the patches that were posted to the mailing list.

I have the same experience with the fan. Adding heavily undervolted standard 12cm fan next to the board is all the cooling needed for pretty much anything. The board can take constant full load at 1.8GHz with no throttling. And I have the worst bin. The best bin could probably take 2GHz or more with slight overvolting and this kind of simple cooling solution. The board is a heatsink. It just has small thermal capacity, so it only cools efficiently if you can move the heat away quickly with a fan.