vTaskGetRunTimeStats() for CPU usage in FreeRTOS - Mini Project: Build & Apply

Using vTaskGetRunTimeStats() to Monitor CPU Usage in FreeRTOS

📖 Scenario: You are working on a FreeRTOS embedded system project. You want to monitor how much CPU time each task is using to optimize your system performance.

🎯 Goal: Build a simple FreeRTOS program that creates two tasks and uses vTaskGetRunTimeStats() to display CPU usage statistics of these tasks.

📋 What You'll Learn

Create two FreeRTOS tasks named Task1 and Task2

Create a buffer string called runtimeStatsBuffer with size 256

Use vTaskGetRunTimeStats(runtimeStatsBuffer) to collect CPU usage stats

Print the CPU usage stats using printf

💡 Why This Matters

🌍 Real World

Monitoring CPU usage helps embedded developers optimize task scheduling and system responsiveness.

💼 Career

Understanding FreeRTOS task monitoring is essential for embedded software engineers working on real-time systems.

1

Create two FreeRTOS tasks

Create two tasks named Task1 and Task2 using xTaskCreate(). Each task should run an empty infinite loop with a small delay using vTaskDelay(pdMS_TO_TICKS(100)).

FreeRTOS

// Create Task1 and Task2 with empty loops
// Your code here

Need a hint?

Use xTaskCreate() to create tasks. Each task runs an infinite loop with vTaskDelay(pdMS_TO_TICKS(100)) to yield CPU.

2

Create a buffer for runtime stats

Create a character array called runtimeStatsBuffer with size 256 to hold the CPU usage statistics string.

FreeRTOS

#include "FreeRTOS.h"
#include "task.h"
#include 

void Task1(void *pvParameters) {
    for (;;) {
        vTaskDelay(pdMS_TO_TICKS(100));
    }
}

void Task2(void *pvParameters) {
    for (;;) {
        vTaskDelay(pdMS_TO_TICKS(100));
    }
}

int main(void) {
    xTaskCreate(Task1, "Task1", 1000, NULL, 1, NULL);
    xTaskCreate(Task2, "Task2", 1000, NULL, 1, NULL);
    vTaskStartScheduler();
    return 0;
}

char runtimeStatsBuffer[256];  // Your code here

Need a hint?

Declare char runtimeStatsBuffer[256]; outside main() or inside before usage.

3

Collect CPU usage stats with vTaskGetRunTimeStats()

Inside main(), after starting the scheduler, call vTaskGetRunTimeStats(runtimeStatsBuffer) to fill the buffer with CPU usage statistics.

FreeRTOS

#include "FreeRTOS.h"
#include "task.h"
#include 

void Task1(void *pvParameters) {
    for (;;) {
        vTaskDelay(pdMS_TO_TICKS(100));
    }
}

void Task2(void *pvParameters) {
    for (;;) {
        vTaskDelay(pdMS_TO_TICKS(100));
    }
}

char runtimeStatsBuffer[256];

int main(void) {
    xTaskCreate(Task1, "Task1", 1000, NULL, 1, NULL);
    xTaskCreate(Task2, "Task2", 1000, NULL, 1, NULL);
    vTaskStartScheduler();
    vTaskGetRunTimeStats(runtimeStatsBuffer);  // Your code here
    return 0;
}

Need a hint?

Call vTaskGetRunTimeStats(runtimeStatsBuffer); after vTaskStartScheduler();.

4

Print the CPU usage statistics

Add a printf statement to print the contents of runtimeStatsBuffer so you can see the CPU usage of each task.

FreeRTOS

#include "FreeRTOS.h"
#include "task.h"
#include 

void Task1(void *pvParameters) {
    for (;;) {
        vTaskDelay(pdMS_TO_TICKS(100));
    }
}

void Task2(void *pvParameters) {
    for (;;) {
        vTaskDelay(pdMS_TO_TICKS(100));
    }
}

char runtimeStatsBuffer[256];

int main(void) {
    xTaskCreate(Task1, "Task1", 1000, NULL, 1, NULL);
    xTaskCreate(Task2, "Task2", 1000, NULL, 1, NULL);
    vTaskStartScheduler();
    vTaskGetRunTimeStats(runtimeStatsBuffer);
    printf("%s", runtimeStatsBuffer);  // Your code here
    return 0;
}

Need a hint?

Use printf("%s", runtimeStatsBuffer); to display the CPU usage stats.