Getting started with AI on NXP i.MX8M Plus - Neural Processing Unit - Use Case experiments: Smart Parking - Bash scripts for CPU usage and time estimation

Getting started with AI on NXP i.MX8M Plus
Introduction
Overview i.MX8M Plus hardware specifications Development tools Development kit DART-MX8M-PLUS Development kit Quick getting started Yocto minimal image Flashing SD card First steps on the board
Development
Gatesgarth and Hardknott Yocto versions Downloading Yocto images for NXP based BSP Building an imx-core-image Flashing SD card Integrating multimedia software stack Installing GStreamer Installing OpenCV Integrating Artificial Intelligence software stack Installing TensorFlow Lite for NXP based images Installing R2Inference Installing GstInference Developing software for the board Building the SDK Crosscompiling apps for GStreamer, TensorFlow Lite, and OpenCV Exploring TensorFlow Lite delegates for prototyping
Neural Processing Unit
Introduction Profiling the NPU Installing gputop Setting the board on debug mode Use Case experiments: Smart Parking Introduction to the use case License Plate Detection TinyYOLO version 3 Training a model compatible with GstInference License Plate Recognition Rosetta Getting the model prototyping Bash scripts for CPU usage and time estimation Serial experiments Parallel Experiments Results
GStreamer
Exploring Rosetta element for character recognition Example pipelines Smart Parking Video inferences Image inferences Video streaming
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Parallel experiment scripts

The following scripts were useful for profiling the performance of Rosetta and TinyYOLO v3 sharing resources on the i.MX8M Plus. These prototypes were developed in C++ before giving the support in the GStreamer wrapper GstInference and R2Inference. Even though the code of the prototype is not available these scripts may help people to profile their applications when parallel execution is needed.

Execution time estimation script

The execution time was taken using the C++ STL High-Precision clock inside the C++ prototype.

# This test is intended to run in parallel two inferences and log
# the performance in time terms.

# Variables for TinyYOLO

TY_INPUT_IMAGE=/car_plate_detection/G1.jpg

TY_OUTPUT_IMAGE=/car_plate_detection/G12.jpg

TY_MODEL=/car_plate_detection/car_plate_tinyYolo_model2.tflite

TY_WR_LOOPS=100

TY_DL=2

TY_THREADS=4

# Variables for Rosetta:
car_plate_recognition

R_INPUT_IMAGE=/car_plate_recognition/prueba.png

R_OUTPUT_IMAGE=/car_plate_recognition/prueba2.png

R_MODEL=/car_plate_recognition/crnn_dr.tflite

R_WR_LOOPS=100

R_DL=3

R_THREADS=4

	
# TinyYOLO inference
./car_plate_detection/test_TinyYOLO $TY_INPUT_IMAGE $TY_OUTPUT_IMAGE $TY_MODEL $TY_WR_LOOPS $TY_DL $TY_THREADS &
TY=$!

# Rosetta inference:
./car_plate_recognition/test_Rosetta $R_INPUT_IMAGE $R_OUTPUT_IMAGE $R_MODEL $R_WR_LOOPS $R_DL $R_THREADS &
RT=$!

wait $TY $RT
	
echo "----------------------------Done------------------------------"

CPU usage estimation script

The CPU usage was taken from this script using the PS Linux command

# This script is intended to check the CPU usage 
# for processes related to TinyYOLO inference and
# Rosetta inference.

# Every 1 second, the script will sample the CPU usage
# for both inferences. So 900s/60s = 15min. Which means
# that for 15 minutes this script will be logging
# the CPU usage.

DURATION=900

TINYYOLO_USAGE=0
YOLO_PREFIX="test_TinyYOLO"
YOLO_RESULTS_TXT="TinyYOLO_CPU_usage.txt"

ROSETTA_USAGE=0
ROSETTA_PREFIX="test_Rosetta"
ROSETTA_RESULTS_TXT="Rosetta_CPU_usage.txt"

for counter in {0..900..1}
do
  TINYYOLO_USAGE=$(ps -eocomm,pcpu | egrep -v '(0.0)|(%CPU)' | grep test_TinyYOLO)
  ROSETTA_USAGE=$(ps -eocomm,pcpu | egrep -v '(0.0)|(%CPU)' | grep test_Rosetta)
  
  if [ -z "$TINYYOLO_USAGE" ]
  then
      echo "tinyYOLO usage: $counter, 0"
      echo "($counter, 0)" >> $YOLO_RESULTS_TXT
  else
      echo "tinyYOLO usage: $counter, ${TINYYOLO_USAGE/#$YOLO_PREFIX}"
      echo "($counter, ${TINYYOLO_USAGE/#$YOLO_PREFIX})" >> $YOLO_RESULTS_TXT
  fi

  if [ -z "$ROSETTA_USAGE" ]
  then
     echo "rosetta usage : $counter, 0"
     echo "($counter, 0)" >> $ROSETTA_RESULTS_TXT
  else
     echo "rosetta usage : $counter, ${ROSETTA_USAGE/#$ROSETTA_PREFIX}"
     echo "($counter, ${ROSETTA_USAGE/#$ROSETTA_PREFIX})" >> $ROSETTA_RESULTS_TXT
  fi
  
  sleep 1   
done