Minimise power consumption in active state when idle

Robotics & Edge Computing Jetson & Embedded Systems Jetson TX2
1

Hi,

I’m trying minimise power consumption on my TX2 (running on batteries) when it isn’t doing anything.
I’ve read through the power management for Jetson TX2 series devices but I was hoping for specific advice for my situation:

  • I need the TX2 to remain in a low power state, then from a hardware trigger grab a frame from a camera
  • Doing this from deep sleep works great, but the delay in waking up is too slow to call the camera (the camera API requires something external to call frame grabbing functions)
  • In the active state, the documentation states the power can be brought down to tens of milliwatts
  • In MAXQ mode my idle TX2 sits at ~1.65W.
  • I know I can create my own custom mode and turn off the other CPUs and bring down frequencies further, but I assume this is negligible because all cores are sitting idle anyway
  • My question is: can anyone help me identify what is taking up the bulk of the 1.65W, and give advice on how to minimise it?
  • Ideally what I would want is the closest thing to deep sleep that still allows me to call a C function and store an image.

In the long term I realise the solution is probably to use a low power microcontroller to do this and pass the data to the jetson after it wakes up, or to get a camera that can store images itself, but I was hoping for any advice for this situation in the mean time.

Many thanks for your time.

1 Like
3

Hi,

You could try to use some tools like “htop” or tegrastats to measure what application is using the resource. Also, do you have peripheral IO on it? For example, HDMI with desktop enabled…

1 Like
4

Thanks for the reply!
Yes it’s on an on orbitty carrrier board. The camera is USB, but other than that I am not using any other IO, though I have not disabled any of these - could they still being drawing power if not plugged in?
Here is the output of htop:

Screenshot from 2020-03-19 07-42-48
Screenshot from 2020-03-19 07-42-481346×776 164 KB

and the output of tegrastats

Screenshot from 2020-03-19 07-59-52
Screenshot from 2020-03-19 07-59-52732×75 12.8 KB

5

Hi,

Just want to confirm. The 1.65W result is in idle mode but not sleep mode,right?
Do you need the ethernet?

6

Yes the power measurement is for idle but awake. Sorry yes I should have mentioned I need ethernet to talk to another device.

7

I just checked the internal test data. Your result is near our internal test result when we put device in idle

  • In the active state, the documentation states the power can be brought down to tens of milliwatts

I saw the internal test with 100mW in SC7. May I know which document did you see above description?

8

The milliwatts quote was from here:

https://docs.nvidia.com/jetson/archives/l4t-archived/l4t-3231/index.html#page/Tegra%2520Linux%2520Driver%2520Package%2520Development%2520Guide%2Fpower_management_tx2_32.html%23wwpID0E0ZS0HA

Under Chipset power States:

*Active state is extraordinarily flexible in terms of power and performance. It encompasses activity levels from low power audio playback through peak performance. Power consumption in the active state can range from tens of milliwatts up to several watts.

11

I don’t think currently we have a tens of miiliwatts usecase. The document points out it is chipset power state.
It probably means the lowest case on tegra SoC.

However, if any OS running on it, then I don’t think it is possible to achieve this value.