Task priority assignment in FreeRTOS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is task priority in FreeRTOS?

Task priority is a number that tells FreeRTOS which task is more important. Higher priority tasks run before lower priority ones.

beginner

How do you assign a priority to a task when creating it in FreeRTOS?

You assign priority by passing a number as the 'uxPriority' parameter in the xTaskCreate() function.

intermediate

What happens if two tasks have the same priority in FreeRTOS?

If two tasks have the same priority, FreeRTOS switches between them in a round-robin way, sharing CPU time fairly.

intermediate

Can task priority be changed after a task is created? How?

Yes, you can change a task's priority anytime using the vTaskPrioritySet() function.

advanced

Why should you avoid giving all tasks the same high priority?

Giving all tasks the same high priority can cause poor system performance because tasks will compete and may starve lower priority tasks.

In FreeRTOS, which task will run first?

A The task with the highest priority number

B The task created first

C The task with the lowest priority number

D The task with the longest name

FreeRTOS runs the task with the highest priority number first.

How do you set the priority of a task when creating it?

A By passing the priority as a parameter to xTaskCreate()

B By calling vTaskPrioritySet() before creating the task

C By naming the task with a priority number

D By setting a global variable

The priority is set by passing it as the 'uxPriority' parameter in xTaskCreate().

What does FreeRTOS do if two tasks have the same priority?

A Runs the task with the lower priority

B Runs them one after the other in round-robin fashion

C Runs the task with the longer name

D Runs only the first created task

FreeRTOS shares CPU time between tasks of equal priority using round-robin scheduling.

Which function changes a task's priority after creation?

A xTaskCreate()

B vTaskDelete()

C vTaskPrioritySet()

D xTaskResume()

vTaskPrioritySet() is used to change a task's priority at runtime.

Why is it bad to give all tasks the same high priority?

A It saves memory

B It makes the system run faster

C It disables task switching

D It can cause tasks to compete and starve others

All tasks with high priority compete for CPU, which can cause poor performance and starvation.

Explain how task priority affects task scheduling in FreeRTOS.

Think about which tasks get CPU time first and how tasks with same priority share time.

Describe how to assign and change task priority in FreeRTOS.

Consider both when creating a task and after it is running.