Productivity as a quality attribute: planning policies
Planning policies are the foundation of effective resource management and ensuring the stable operation of systems. They determine how tasks are distributed and executed, considering various criteria such as priority, deadlines, or order of arrival.
Main scheduling strategies:
🔹 FIFO (First-In-First-Out):
Tasks are executed in the order they arrive. This is a simple and intuitive method, but if one task takes too long, it may cause delays for others.
🔹 Fixed priority scheduling:
Tasks are assigned priority according to predefined rules:
Semantic importance: Priority is determined by the significance of the task for the system.
Deadline monotonicity: Tasks with shorter deadlines receive higher priority.
Frequency monotonicity: Suitable for periodic tasks—shorter intervals correspond to higher priority.
🔹 Dynamic scheduling:
Task priority can change depending on their characteristics and the system’s state:
- Round-robin: Tasks are executed in turns, ensuring fair time distribution.
- Earliest deadline first: Preference is given to tasks with the shortest time until the deadline.
- Shortest remaining time: The task with the least remaining time until completion is selected.
Choosing the right scheduling policy helps achieve a balance between execution speed, fairness, and efficient resource utilization. Understanding these strategies is a step toward optimizing system performance and enhancing productivity.