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Context Switching

Intermediate
Processes & Threads

Context switching is the process of storing and restoring the state of a CPU so that multiple processes or threads can share a single CPU resource.

Overview

When a CPU switches from executing one process or thread to another, it saves the state of the current process (registers, program counter, etc.) and loads the state of the next process. This is essential for multitasking but introduces overhead.

Steps in Context Switching

1. Save the state of the current process. 2. Update the process control block (PCB). 3. Load the state of the next process. 4. Update the CPU scheduler. Context switching is managed by the OS kernel and is a key feature of preemptive multitasking.

Pseudocode — Context Switching
// Simulating context switching in pseudocode
while (true) {
    save_state(current_process);
    current_process = scheduler.get_next_process();
    load_state(current_process);
}

Performance Implications

Frequent context switches can degrade performance due to the overhead of saving and restoring states. Minimizing context switches is crucial for real-time systems.

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