thermal sensor of TK1

I try to read TK1’s chip temperature and control it by DVFS. In default, it reports the CPU, GPU, MEM, and other components temperature. However, it has 1 CPU temperature but physically includes 4+1 CPU cores, so what the CPU temperature is exactly for? Is it an average temperature of CPU cores, or whatever?

Also, I find that when the reported CPU temperature is in 60C-70C, the whole system becomes very unreliable. The whole file system becomes read-only, and some user processes are terminated randomly. Could someone help to explain?

I can’t answer your question, but you’ll probably also want to mention if CPU speed throttling is still enabled (the default), or if performance mode has been forced. As to processes terminating, if you have a rough idea of how much memory is used (or better yet, “/proc/meminfo”) before terminations start that too might be useful for someone answering (process termination could be hardware issues, but could also be a sign of memory being used up, e.g., via memory leak, followed by normal methods of the o/s dealing with it). If it turns out memory is heavily used and nearing limits, you might want to create swap space on a SATA drive or flash card and run with extra swap to see if process terminations change.

There are eight on-die thermal sensors are placed close to dominant potshots for high accuracy sensing of junction temperature maximums. Seven of the sensors are grouped into three thermal zones: one strongly influenced by the CPU, one strongly influenced by the GPU, and one strongly influenced by the DRAM memory controller and interface. The one remaining sensor plays a support role to the other seven. A hardware controller, called SOC_THERM, can directly read the sensors, initiate thermal throttling, and/or interrupt software at various temperature points.
60-70c is not hot for CPU temperature and won’t trigger thermal throttling.
The system shutdown temperature usually set to 105c.
80~90c trip point for thermal throttling and can be read out from system node.

Thank you so much. May I know where are these sensors. I doubt that different cores may have different temperatures, so If the temperature sensor for CPU is 60C, is this an average value of 4 cores?

I also find that at first, I run a benchmark in a specific core with a specific frequency, then I got a temperature T1. Then, running the same benchmark in the same core, same frequency, and keeping other thing changes, I got a temperature T2. I expect that T1 and T2 should be similar, but somethings, there are 20C difference between T1 and T2.

The thermal sensors are inside tegra processor, The CPU temp represent the temperature close to Cortex CPU area, There is no independent sensor for each core.
Would you please run benchmark for long time and record the stable temperature.
20C difference is not reasonable