Task pooling for dynamic workloads in FreeRTOS - Mini Project: Build & Apply

Task pooling for dynamic workloads

📖 Scenario: You are building a FreeRTOS application that needs to handle multiple tasks dynamically. Instead of creating and deleting tasks repeatedly, you want to use a task pool to reuse tasks efficiently. This helps save system resources and improves performance.

🎯 Goal: Build a simple task pool system in FreeRTOS where a fixed number of tasks wait for work from a queue. When new work arrives, a task picks it up, processes it, and then waits for more work. You will create the data structures, configure the queue, implement the task pool logic, and print the results.

📋 What You'll Learn

Create an array of task handles for the task pool

Create a FreeRTOS queue to hold work items

Implement worker tasks that wait on the queue and process work

Print the processed work item IDs from the tasks

💡 Why This Matters

🌍 Real World

Task pooling is used in embedded systems to efficiently manage limited resources by reusing tasks instead of creating and deleting them repeatedly.

💼 Career

Understanding task pooling and FreeRTOS queues is important for embedded software developers working on real-time systems like IoT devices, automotive controllers, and industrial automation.

1

Create the task pool handles array

Create an array called taskPool of type TaskHandle_t with size 3 to hold the task handles.

FreeRTOS

# Create an array called taskPool of type TaskHandle_t with size 3
# Your code here

Need a hint?

Use the syntax TaskHandle_t arrayName[size]; to declare the array.

2

Create the work queue

Create a queue handle called workQueue using QueueHandle_t. Then create the queue with xQueueCreate to hold 5 integers representing work item IDs.

FreeRTOS

TaskHandle_t taskPool[3];
// Create a queue handle called workQueue and create the queue for 5 integers
# Your code here

Need a hint?

Use QueueHandle_t for the queue handle and xQueueCreate(5, sizeof(int)) to create the queue.

3

Implement the worker task function

Write a function called workerTask that takes void *pvParameters. Inside, declare an integer workItem. Use an infinite loop to call xQueueReceive on workQueue with portMAX_DELAY. When a work item is received, print its ID using printf with the format "Task processed work item: %d\n".

FreeRTOS

TaskHandle_t taskPool[3];
QueueHandle_t workQueue;
workQueue = xQueueCreate(5, sizeof(int));

// Write the workerTask function below
# Your code here

Need a hint?

Use an infinite loop with for (;;) and xQueueReceive to wait for work.

4

Create tasks and send work items

Create 3 tasks using xTaskCreate with workerTask, names "Worker1", "Worker2", "Worker3", stack size 1000, no parameters, priority 1, and store their handles in taskPool. Then send 5 work items (integers 1 to 5) to workQueue using xQueueSend. Finally, start the scheduler with vTaskStartScheduler().

FreeRTOS

TaskHandle_t taskPool[3];
QueueHandle_t workQueue;
workQueue = xQueueCreate(5, sizeof(int));

void workerTask(void *pvParameters) {
    int workItem;
    for (;;) {
        if (xQueueReceive(workQueue, &workItem, portMAX_DELAY) == pdPASS) {
            printf("Task processed work item: %d\n", workItem);
        }
    }
}

// Create 3 tasks, send 5 work items, and start scheduler
# Your code here

Need a hint?

Use xTaskCreate to create tasks and xQueueSend to send work items.