Thank you @JerryChang for your response. tegrastats utility has a lot of statistics but, I did not find anything specific for CPU core voltage. I am looking for commands similar to the Raspberry Pi utility command “vcgencmd measure_volts core”, which gives the CPU core voltage at any instance of time. Do we have any such utility available for Nvidia Jetson Nano?
I am conducting some energy consumption experiments using DVFS (Dynamic Voltage and Frequency Scaling) and will possibly be writing a paper on that. I scale the CPU frequency from userspace as per my application requirement. I need to see how the CPU core voltage scales with respect to frequency scaling to justify my results.
suggest you should work with Nano platforms instead of Nano-2GB.
you’ll need to specify regulators if you’re having your driver implementation.
there’re regulators that defined in device tree for driver’s usage. you may look into the nodes, monitor the voltage changes with your use-case,
here’s sysnode for checking all regulators,
for example, /sys/kernel/debug/regulator/regulator_summary.
I do not have any driver implementation. My experiment goal is to use DVFS to save energy in my experiment. I ran a dummy experiment of computing a sum of 1500000 random floating-point numbers. I used the frequencies [‘102000’, ‘307200’, ‘518400’, ‘710400’, ‘921600’, ‘1132800’, ‘1326000’, ‘1479000’] and measured the energy using a power meter. I observed that the energy consumed for each of the frequencies [‘102000’, ‘307200’] to be around 63 milli watt-hours. Similarly the energy consumed for each of the frequencies [‘518400’, ‘710400’, ‘921600’, ‘1132800’, ‘1326000’, ‘1479000’] remains around 84 milli watt-hours.
Changing only the frequency affects execution time but does not affect the energy consumption of the operation. However, a change in voltage affects energy consumption. From the result above, I believe there are only two voltage levels supported. A low voltage for frequencies [‘102000’, ‘307200’] and a higher voltage for frequencies [‘518400’, ‘710400’, ‘921600’, ‘1132800’, ‘1326000’, ‘1479000’] . To confirm my belief, I was trying to find the voltage corresponding to each frequency. Will you be able to check on this frequency to voltage mapping of Jetson Nano 2GB and confirm that this is actually the case?
Could you please let me know, which regulator file will have the CPU core voltage?
I grepped on vdd-cpu in
/sys/kernel/debug/regulator/regulator_summary, but it does not change. It remains the same at 708mV for all the CPU frequencies.
Could you please help me with the regulator file name that holds the current CPU core voltage?