What is the Difference Between Multithreading and Multiprocessing in Embedded Linux?

Multiprocessing

Multiprocessing, also known as processes, refers to independent programs running in their own memory space.

Each process has its own address space, code, data, and stack.

Communication between processes requires IPC mechanisms (pipes, message queues, shared memory, sockets).

When to Use?

You want isolation (one process crashing does not affect other processes).

Embedded example: Running a sensor daemon separately from the communication service so they do not interfere with each other.

Multithreading

A thread is a lightweight execution unit within a process.

All threads in a process share the same memory space (code, data, heap), but each thread has its own stack and registers.

Communication between threads is easier (they directly share memory), but synchronization (mutexes, signals) is needed to avoid race conditions.

When to Use?

Do you want to perform tasks in parallel within a single application?

Embedded example: One thread reads sensor data, another thread handles MQTT communication, and another thread refreshes logs—all within the same application.

Key Differences

Process = heavy, isolated, slower to create, more secure.

Thread = lightweight, fast, shared memory, but with greater risk (a bad thread can corrupt shared data).

Conclusion

In Embedded Linux, a process is an independent program with its own memory space, while a thread is a lightweight unit within a process that shares the same memory. We use multiple processes when isolation is needed, such as separating sensor services from communication services. We use threads when we need tasks to share memory and run concurrently within the same application, such as reading sensors and processing network communication in parallel.