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CPU temp and governor control?

PostPosted: Tue Nov 21, 2017 4:44 pm
by marcdraco
Here's a thought - and it seems the sort of thing that might be suitable for Cron job but I don't know the ins-out of how things work on this bit:

I've noticed that the Orange Pi (and presumably others) have CPU governors to throttle the system and a CPU command that tells us how warm our oven is and if it's time to put the roast in.

Joking aside, my OPi sits in a room currently about 10 C and even with a copper sink, it's still more than capable of running itself to the point where the SOC is ready to burn out. During a busy period, I had to throttle it back to just 600 MHz (I know right!) to stop it passing the 60 C mark.

This sounds like a job for a simple script to monitor the CPU temp (perhaps every minute) and if the temperature exceeds a certain point, to throttle back for a while until it drops to a preset limit.

Now there IS a problem here... constantly heating and cooling the solder is a sure way to break something due to a stress fracture and that could conceivably shorten the life of the board. It's the sort of thing that needs careful consideration but I wonder if it's worth adding in to the existing system?


UPDATE - it's not just the clock speed but also the SOC's other work that generates heat - this is after doing several hours of work over USB shifting data between a couple of drives. Remember this is in a room at 10 C ambient and with a heatsink. If this had bee pegged at 1.3G, it would likely have burned out the SOC in an couple of hours.

Architecture | armv7l
Temp | 52'c | Running warm, but safe.
Governor | ondemand
Throttle up | 95% CPU usage

Current Freq Min Freq Max Freq
CPU0 | 864 MHz 60 MHz 864 MHz
CPU1 | 864 MHz 60 MHz 864 MHz
CPU2 | 864 MHz 60 MHz 864 MHz
CPU3 | 864 MHz 60 MHz 864 MHz