Identify Current Task Prioritization
Understand System Requirements and Task Dependencies
- List all tasks with their current priorities and perform a criticality analysis. Identify which tasks are time-critical and should have a higher priority.
- Determine dependencies between tasks. A dependent task should generally have a lower priority than the task it depends on.
- Assess the overall system requirements and constraints, such as real-time deadlines, to justify and adjust priorities.
Reassign Task Priorities
- Based on the analysis, reorder task priorities. Use your RTOS API to set task priorities correctly. For example, in FreeRTOS, use `vTaskPrioritySet()`.
```c
vTaskPrioritySet(taskHandle1, 2); // Lower priority
vTaskPrioritySet(taskHandle2, 4); // Medium priority
vTaskPrioritySet(taskHandle3, 6); // High priority
```
- Ensure that higher-priority tasks do not consume all CPU time, leading to task starvation. Implement time-slicing if necessary.
- Consider priority inheritance mechanisms if priority inversion problems exist.
Test and Validate Prioritization Changes
- Deploy the updated task prioritization to a test environment. Use simulations to emulate different system loads and behavior.
- Monitor resource utilization and task execution times to ensure that higher-priority tasks meet their deadlines without impacting lower-priority tasks significantly.
- Use assertions or diagnostic messages in task loops to verify expected behavior and catch edge cases.
```c
if (uxTaskPriorityGet(NULL) != expectedPriority) {
printf("Priority mismatch detected.\n");
}
```
Optimize and Document Task Prioritization
- After validation, optimize priority levels by minimizing the number of priority levels used, which can simplify scheduling without losing performance benefits.
- Document the rationale for task prioritization in system documentation for future reference and maintenance.
- Periodically review and update task priorities in response to system requirement changes, bug reports, or performance evaluations.
