who initiates priority in scheduling in RTOS?

Question

How priority is initialized in RTOS? who will initiate priority for scheduling?

Answer 1

Most RTOS have between 32 and 256 possible priorities for individual tasks/processes. The scheduler will run the task with the highest priority. When a running task gives up the CPU, the next highest priority task runs, and so on...

The highest priority task in the system will have the CPU until:

• it runs to completion (i.e. it voluntarily give up the CPU)
• a higher priority task is made ready, in which case the original task is pre-empted by the new (higher priority) task.
  As a developer, it is your job to assign the task priorities such that your deadlines will be met.