Threads and Multithreading

Threads are lightweight execution units within a process that enable concurrent execution while sharing the same memory space and resources. Unlike processes which have separate memory spaces, threads within the same process share code, data, and system resources but have their own stack, registers, and program counter. This makes thread creation, context switching, and communication more efficient than processes. Threads can be implemented at the user level (managed by a user-space library) or kernel level (managed by the operating system). User-level threads are faster to create and manage but cannot leverage multiple processors, while kernel-level threads can run on multiple processors but have higher overhead. Multithreading allows applications to perform multiple tasks concurrently, improving responsiveness and resource utilization. Common threading models include one-to-one (each user thread maps to one kernel thread), many-to-one (many user threads map to one kernel thread), and many-to-many (many user threads map to many kernel threads). Thread synchronization mechanisms like mutexes, semaphores, and condition variables are essential to prevent race conditions when threads access shared resources. Understanding threads and multithreading is crucial for developing responsive, efficient applications that can leverage modern multi-core processors effectively.