Starvation

Definition

Starvation refers to a condition where a process is perpetually denied the resources it needs to proceed with its execution, often due to scheduling policies or resource allocation methods. This state can arise in various situations, particularly when certain processes monopolize the CPU or resources, leading to others being indefinitely postponed. Understanding starvation is crucial in evaluating how processes interact and compete for resources in multitasking environments.

5 Must Know Facts For Your Next Test

1. Starvation can occur in systems using priority-based scheduling if high-priority processes continually preempt lower-priority ones, preventing them from running.
2. To mitigate starvation, systems may implement aging, which gradually increases the priority of waiting processes over time.
3. Starvation is often more pronounced in environments with limited resources or many competing processes trying to access those resources.
4. Deadlock and starvation are different; deadlock involves a circular wait condition while starvation occurs due to unfair resource allocation.
5. Some operating systems provide guarantees or mechanisms, like round-robin scheduling, to minimize or eliminate starvation for lower-priority processes.

Review Questions

• How does starvation differ from deadlock, and what implications does this have for process management?
  • Starvation differs from deadlock in that it involves a process being indefinitely postponed due to resource allocation policies rather than being stuck in a circular wait. While deadlock involves multiple processes that cannot proceed because they are waiting for each other, starvation can occur even when resources are available but are not allocated fairly. This has significant implications for process management as it highlights the need for balanced scheduling algorithms that prevent both conditions and ensure all processes can make progress.
• Discuss the role of priority scheduling in contributing to starvation and the methods that can be employed to prevent it.
  • Priority scheduling can significantly contribute to starvation as lower-priority processes may be overlooked indefinitely if higher-priority processes are always present. This creates a situation where important tasks may never complete due to constant preemption. To prevent starvation, techniques such as aging can be used, where the system gradually increases the priority of waiting processes, ensuring they eventually receive CPU time. Additionally, implementing fair scheduling policies can help balance the needs of all processes.
• Evaluate the effectiveness of aging as a solution for preventing starvation and discuss potential drawbacks.
  • Aging is an effective solution for preventing starvation as it systematically raises the priority of processes that have been waiting for an extended period. This ensures that even lower-priority tasks eventually get executed, fostering fairness in resource allocation. However, there are potential drawbacks, such as increased complexity in scheduling algorithms and possible inefficiencies if high-priority tasks are delayed longer than intended. Balancing aging with immediate responsiveness for critical tasks remains a challenge in design.

Related terms

Fairness: Fairness is the principle that each process should receive a fair share of resources and CPU time, preventing any single process from starving other processes.

Resource Allocation: Resource allocation involves the method by which resources like CPU time, memory, and I/O devices are assigned to processes to ensure efficient system operation.

Priority Scheduling: Priority scheduling is a technique where processes are assigned a priority for execution, which can inadvertently lead to starvation if lower-priority processes are never scheduled.