Power Monitoring on Jetson TX2

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

Hello,

I’m performing an analisis of power consumption of CNN ( with the trtexec tool ) on Jetson TX2, varying the Host and Device frequencies.

In the past I have performed this power analisis through a multimeter,
in which I measured the current that flows from my lab power supply ( set at 19 Volts ) to the carrier board. Then through the Ohm law, I algebrically obtained the power consumption of the carrier board.
Finally I have subtracted from this consumption, the power consumed when the SoC is in idle.
For sure this is not an optimal methodology but I guess that it give an idea of the power consumption of the TX2 SoC.

Recently I’m trying to do the same, not with the multimeter, but through the INA3221 sensor inside the board.
I created a script that read the input power of the SoC rail: in_power1_input.

The problem is that this two results are very different: about 4 Watt with the multimeter and about 0.9 Watt with the sensor.
I am not an expert in electronics and power consumption of embedded systems, but I think that 0.9 Watt at the maximum GPU and CPU frequency is too low.

Maybe the SoC rail does not consider the GPU consumption? or the INA sensor does not capture something that in reality consumes power or something similar?

Thanks

2

Hi HeroGian, if you are reading in_power1_input, that would indicate that you are measuring the VDD_SOC power rail. VDD_SOC indicates miscellaneous SoC power (without CPU/GPU/memory/ect.) and does not reflect the total module power consumption. For that, please measure the VDD_IN rail:

$ cat /sys/bus/i2c/drivers/ina3221x/0-0041/iio_device/rail_name_0
VDD_IN
$ cat /sys/bus/i2c/drivers/ina3221x/0-0041/iio_device/in_power0_input
2304

(above was captured during idle, MAX-N mode)

Please refer to Table 6-1 of the Jetson TX2 Thermal Design Guide for the addressing of the other power rails.
Note that as shown in the console output above, VDD_IN is located at address 0-0041 (channel 0)

1 Like
3

Thanks, I tried to read this rail and actually is similar to what I seen with the multimeter.
VDD_IN does not consider the consumption of the Jetson board, but only the power dissipated on the Tegra SoC right?

4

VDD_IN is the source of all power rails of module.