Multithreading - aryanjoshi0823/5143-Operating-System GitHub Wiki

Multithreading is a technique where multiple threads within a single process execute concurrently. Each thread shares the process's resources, such as memory, data, and files, but operates independently.

For example, a web browser uses multithreading to handle multiple tasks simultaneously, such as rendering a webpage, downloading files, and running scripts.

Multithreading Models:

Operating systems implement multithreading using the following models:

1. Many-to-One Model:

  • Description: Multiple user-level threads are mapped to a single kernel thread.
  • Advantages:
    • Simple and efficient to implement.
    • Suitable for systems with limited kernel thread support.
  • Disadvantages:
    • One thread's blocking operation can block the entire process.
    • Limited utilization of multi-core processors.

2. One-to-One Model:

  • Description: Each user-level thread is mapped to a separate kernel thread.
  • Advantages:
    • Provides true concurrency.
    • Allows threads to run on multiple cores simultaneously.
  • Disadvantages:
    • Higher overhead due to the creation of kernel threads.
    • Limited scalability due to restrictions on the number of kernel threads.

3. Many-to-Many Model:

  • Description: Multiple user-level threads are mapped to a smaller or equal number of kernel threads.
  • Advantages:
    • Combines the benefits of many-to-one and one-to-one models.
    • Offers better resource utilization and scalability.
  • Disadvantages: Complex implementation.

Applications of Multithreading:

  1. Web Servers: Handle multiple client requests simultaneously.
  2. Database Systems: Perform parallel queries and manage concurrent transactions.
  3. Gaming: Separate threads handle rendering, user input, and game logic for smoother performance.
  4. Real-Time Systems: Ensure responsiveness by allocating threads to time-sensitive tasks.
  5. Multimedia Applications: Stream audio, video, and process user input concurrently.