Starvation

Definition

Starvation is a condition that occurs when a process is unable to gain access to the necessary resources or time to complete its task, often due to the actions of other processes. This term is particularly significant in the context of resource allocation and scheduling in concurrent programming, as it highlights the potential for some processes to be perpetually denied execution while others proceed, leading to inefficiency and potential system failure.

5 Must Know Facts For Your Next Test

1. Starvation can occur in systems where certain processes hold onto resources longer than necessary, causing other processes to wait indefinitely.
2. Using priority-based scheduling can lead to starvation if lower-priority processes are perpetually preempted by higher-priority ones.
3. Immutability can help reduce the chances of starvation in concurrent programming by ensuring that shared data cannot be modified unexpectedly, allowing for predictable access patterns.
4. Starvation is a significant concern in real-time systems where timely execution is crucial for functionality, as it can lead to missed deadlines and system failures.
5. Implementing fair scheduling algorithms, like round-robin or fair queueing, can mitigate the risk of starvation by ensuring that all processes receive a fair share of CPU time.

Review Questions

• How does starvation differ from deadlock in concurrent programming?
  • Starvation and deadlock are both issues that affect process execution but differ fundamentally. In deadlock, two or more processes are stuck waiting for each other to release resources, resulting in a standstill where none can proceed. In contrast, starvation occurs when a process is perpetually denied the necessary resources to execute due to other processes being favored, even if those other processes are not waiting on one another. This means that while deadlock results in complete halting, starvation leads to certain processes remaining inactive over time.
• What are some strategies that can be implemented to prevent starvation in concurrent systems?
  • To prevent starvation in concurrent systems, several strategies can be employed. Implementing fair scheduling algorithms like round-robin ensures that all processes receive an equitable amount of CPU time. Additionally, priority aging can be used; as a process waits longer in the queue, its priority gradually increases until it eventually gets executed. These methods help ensure that no process is indefinitely delayed and that all have an opportunity to run.
• Evaluate the impact of immutability on the occurrence of starvation in concurrent programming scenarios.
  • Immutability plays a crucial role in reducing starvation by creating predictable access patterns among concurrent processes. When data structures are immutable, they cannot be modified by any process after creation, which eliminates unexpected changes that could lead to contention for resources. This predictability helps minimize waiting times for access to shared resources since processes do not have to compete over mutable states. Consequently, this can lead to more efficient resource usage and decrease the chances of starvation occurring within the system.

Related terms

Deadlock: A situation in concurrent programming where two or more processes are unable to proceed because each is waiting for the other to release resources.

Resource Allocation: The method by which resources such as memory, processing power, and input/output operations are distributed among competing processes in a system.

Concurrency:

The execution of multiple processes or threads simultaneously, often requiring careful management to ensure that shared resources are accessed safely and efficiently.