Resource usage issue jetson nano

Hello there, i am currently trying to get collision avoidance working using resnet18, the problem is, after a while, the blocked value updates way too slowly (initially it works, after loading the model), when i run a command to see cpu and gpu usage , the cpu and gpu also work in that initial state (they get to almost 100%) and the blocked value updates and then after a while it doesnt update as often and the usages drop to almost 10% on the cpu and 0% on gpu

I do get a warning: system throttled due to over-current
what i have tried: optimising the model as much as i can for lower inference time, changing termal paste, hooking up the jetson nano to a lab bench and running it at 5v+2.5A (to get 10W), running the jetson_clocks script
I am using a jetson nano 4gb devkit with a 100mb sd card

I should also mention the DC drivers are controlled using a arduino uno via serial

this is the code i am running:

import torch
import torchvision
import torchvision.transforms as transforms
import torch.nn.functional as F
import cv2
import PIL.Image
import numpy as np
import traitlets
from IPython.display import display
import ipywidgets.widgets as widgets
import threading
from torch2trt import TRTModule

# Import Robot class and other required modules
from Robot import robot_serial
from jetcam.utils import bgr8_to_jpeg
from jetcam.csi_camera import CSICamera

import time

# Initialize the camera
camera = CSICamera(width=224, height=224, capture_width=224, capture_height=224, capture_fps=5)  # Set capture_fps to 10

# Initialize the robot
robot = robot_serial()

device = torch.device('cuda')

# Initialize the model
model_trt = TRTModule()

mean = torch.Tensor([0.485, 0.456, 0.406]).cuda().half()
std = torch.Tensor([0.229, 0.224, 0.225]).cuda().half()

normalize = transforms.Normalize(mean, std)

# Create widgets for display
image_w = widgets.Image(format='jpeg')
blocked_slider = widgets.FloatSlider(description='blocked', min=0.0, max=1.0, orientation='vertical')
speed_slider = widgets.FloatSlider(description='speed', min=0.0, max=1.0, value=0.0, step=0.01, orientation='horizontal')

# Display widgets
display(widgets.VBox([widgets.HBox([image_w, blocked_slider]), speed_slider]))

# Create a threading Event for synchronization
camera_event = threading.Event()

# Introduce frame skipping mechanism
frame_skip = 1  # Skip every 5th frame
frame_count = 0

def clamp(n, min, max):
    if n < min:
        return min
    elif n > max:
        return max
        return n

# Initialize cam_data and a lock for synchronization
cam_data = None
cam_data_lock = threading.Lock()

# Define the camera thread
def camera_thread():
    global cam_data, frame_count
    while True:
        new_cam_data =
        with cam_data_lock:
            cam_data = new_cam_data
        image_w.value = bgr8_to_jpeg(new_cam_data)
        frame_count += 1

        # Signal camera update every frame_skip frames
        if frame_count % frame_skip == 0:

# Start the camera thread
camera_thread = threading.Thread(target=camera_thread)
camera_thread.daemon = True

def preprocess(image):
    # Ensure the image has a correct shape (HWC) and data type (uint8)
    if len(image.shape) == 4 and image.shape[0] == 1:
        image = image[0]

    image = PIL.Image.fromarray(image.astype('uint8'))
    image = transforms.functional.to_tensor(image).to(device).half()
    image.sub_(mean[:, None, None]).div_(std[:, None, None])
    return image[None, ...]

# Define the main loop
def main_loop():
    while True:
        camera_event.wait()  # Wait for camera update
        start_time = time.time()

        with cam_data_lock:
            x = np.array([cam_data], dtype=np.uint8)
        x = preprocess(x)

        with torch.no_grad():
            y = model_trt(x)
            y = F.softmax(y, dim=1)

        end_time = time.time()
        inference_time = end_time - start_time
        #print("Inference Time:", inference_time)

        prob_blocked = float(y[0, 0])
        blocked_slider.value = prob_blocked

        if prob_blocked < 0.5:
            robot.forward(0, clamp(int((speed_slider.value * 100) - 20), 0, 100))
            robot.turnLeft(0, clamp(int(speed_slider.value * 100), 0, 100), clamp(int((speed_slider.value * 100) - 10), 0, 100))
        # Clear the event for the next update and free up memory by deleting variables that are no longer needed.
        del x, y, start_time, end_time, inference_time

# Start the main loop in a separate thread
main_thread = threading.Thread(target=main_loop)
main_thread.daemon = True

sorry if what i said is confusing, english is not my main language, i will clear things up if asked
thank you!


How about memory?
Could you also check the memory status with sudo tegrastats at the initial and the time it gets stuck?


Hello, ive managed to fix it, the issue was that i kept spamming the commands to the arduino, ive changed it to remember the last command and now it works properly.

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