Difference between Multiprocessing and Multithreading

Both multiprocessing and multithreading are used in computer operating systems to increase its computing power. The fundamental difference between multiprocessing and multithreading is that multiprocessing makes the use of two or more CPUs to increase the computing power of the system, while multithreading creates multiple threads of a process to be executed in a parallel fashion to increase the throughput of the system.

In this article, we will discuss all the important differences between multiprocessing and multithreading. Let's start with some basics of multiprocessing and multithreading so that it becomes easier to understand how they are different from each other.

What is Multiprocessing?

Multiprocessing refers to using multiple CPUs/processors in a single system. Multiple CPUs can act in a parallel fashion and execute multiple processes together. A task is divided into multiple processes that run on multiple processors. When the task is over, the results from all processors are compiled together to provide the final output. Multiprocessing increases the computing power to a great extent. Symmetric multiprocessing and asymmetric multiprocessing are two types of multiprocessing.

Multiprocessing increases the reliability of the system because of the use of multiple CPUs. However, a significant amount of time and specific resources are required for multiprocessing. Multiprocessing is relatively more cost effective as compared to a single CPU system.

What is Multithreading?

Multithreading refers to multiple threads being executed by a single CPU in such a way that each thread is executed in parallel fashion and CPU/processor is switched between them using context switch. Multithreading is a technique to increase the throughput of a processor. In multithreading, accessing memory addresses is easy because all of the threads share the same parent process.

The switching among different threads is fast and efficient. It must be noted that in multithreading, multiple threads are created from a single process and then these threads are processed simultaneously.

Difference between Multiprocessing and Multithreading

The following table highlights the major differences between Multiprocessing and Multithreading −

Factor	Multiprocessing	Multithreading
Concept	Multiple processors/CPUs are added to the system to increase the computing power of the system.	Multiple threads are created of a process to be executed in a parallel fashion to increase the throughput of the system.
Parallel Action	Multiple processes are executed in a parallel fashion.	Multiple threads are executed in a parallel fashion.
Categories	Multiprocessing can be classified into symmetric and asymmetric multiprocessing.	No such classification present for multithreading.
Time	Process creation is time-consuming.	Thread creation is easy and is time savvy.
Execution	In multiprocessing, many processes are executed simultaneously.	In multithreading, many threads are executed simultaneously.
Address space	In multiprocessing, a separate address space is created for each process.	In multithreading, a common address space is used for all the threads.
Resources	Multiprocessing requires a significant amount of time and large number of resources.	Multithreading requires less time and few resources to create.

Conclusion

The most significant difference between multiprocessing and multithreading is that multiprocessing executes many processes at the same time, whereas multithreading executes many threads of a process at the same time.