Livelock in Operating System


Introduction

Livelock is a phenomenon that may happen in distributed systems, such as Linux and Windows, when multiple processes or strings constantly alter their states in reaction to changes in the state of other threads or processes, but neither of them may advance toward their goal. Livelock and deadlock are similar in that either scenario may outcome in an arrangement that cannot progress. Procedures or threads aren't really blocked in Livelock; they're just not moving. In this article, we will learn about Livelock, its working in an Operating System, why it must be avoided, and its various disadvantages.

How does Livelock work in an Operating System?

The primary root cause of livelock is the interaction of processes or threads alongside other processes and with resources that are shared such as locks, semaphores, and or other alignment primitives. While more than one process or thread competes for a common asset, their states may constantly change, distributing and actually acquiring the resource at all times in response to changes in the states of the other processes. As a result, no threads or processes can advance, and the entire system is successfully stuck in a loop.

Look at the following situation: two processes in opposite directions are trying to negotiate a narrow bridge. When both procedures try to get over the bridge at exactly the same time, they will come together and be forced to reverse. If each of the procedures uses participation rules to negotiate the border, they could end up remaining in a livelock, in which case they keep supporting up and attempting again with no making any progress.

Livelock can also occur in more complex scenarios involving multiple processes or threads with more complicated interactions. In a distributed system, for example, one process may be waiting for a message from another, while the other process is waiting for a message from the first. If both processes continue to wait for the other to send a message, they may enter a livelock.

Why Livelock Must be Avoided in an Operating System

To avoid livelock, various techniques such as avoiding deadlock algorithms highest priority inheritance procedures, and methods for distributing resources can be used. Deadlock avoidance algorithms use a set of heuristics to identify and prevent circumstances that may give rise to livelock or deadlock. Particular attention to inheritance protocols that ensure that a process that maintains a resource is given priority if a different procedure continues to wait for that resource. Allocation of assets techniques is able to be employed in order to guarantee that assets are allocated in a fair and efficient manner, reducing the probability of conflict.

Livelock is typically seen as a problem or disadvantage in Linux and other distributed systems. However, a few investigators have suggested employing livelock to enhance the efficiency of networks of computers in certain scenarios. This is called "active waiting" or "spin-waiting."

Instead of blocking or sleeping, the idea behind active wait is to keep processes or threads busy while waiting for a resource. The process or thread can make better use of available resources and potentially reduce overall system latency by constantly checking for resource availability and performing other useful work while waiting.

When the resource being waited on is expected to become available quickly or when the cost of blocking or sleeping is relatively high, the active wait can be useful. Active wait, for example, can be used in a high-performance network protocol stack to reduce the overhead of context switching and thread creation when waiting for incoming packets.

It is important to note, however, that active wait can be problematic and cause livelock or other issues if not implemented carefully. In the context of the specific system and workload, the trade-offs between active wait and other synchronization strategies must be carefully considered and evaluated.

Disadvantages of Livelock in Operating System

In operating systems and distributed systems, livelock is generally regarded as a disadvantage because it can result in a system that makes no progress, wasting valuable resources and causing delays. The following are some of the specific disadvantages of a livelock −

Resource Contention − Livelock typically occurs when two or more processes or threads compete for a shared resource, such as a lock or a semaphore. This contention can cause delays and reduce overall system performance.

Increased overhead − In a livelock situation, processes or threads may continue to work even though they are not progressing toward their goal. This can result in increased overhead as resources are consumed without producing useful results.

Difficulty in detecting and diagnosing − Livelock, especially in complex distributed systems, can be difficult to detect and diagnose. Interactions between processes or threads can be difficult to predict, and the system may appear to be operating normally despite the fact that no progress is being made.

Risk of cascading failure − A livelock affecting critical system components can cause cascading failures and further disruptions. A livelock condition, for example, can cause widespread data corruption or loss if it affects a critical database server.

Increased complexity − Because additional mechanisms and strategies are required to detect and avoid livelock conditions, livelock can increase the complexity of a system. This can raise the system's development and maintenance costs.

Conclusion

Livelock is a condition that occurs in operating systems and distributed systems when multiple processes or threads become stuck in a loop and are unable to progress despite continuing to consume resources. Livelock is generally regarded as a disadvantage because it can cause resource contention, increased overhead, difficulty in detecting and diagnosing, cascading failure risk, and increased complexity. Some researchers, however, have proposed using livelock in specific scenarios, known as active wait or spin-wait, to improve performance. Overall, it is critical to detect and avoid livelock conditions in order to ensure the reliability and performance of operating systems and distributed systems.

Updated on: 03-May-2023

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