Updated April 12, 2023

Difference Between Multithreading vs Multiprocessing

The following article provides an outline for Multithreading vs Multiprocessing. One independent application can have multiple processor instances while execution. Each of the single processes can be allocated to a single thread or group of thread for the processing unit to execute them parallelly which can utilize the processing unit. Multithreading refers to executing more than one thread parallelly to achieve the maximum utilization of the CPU.

Multiprocessing refers to the ability of a computer system which supports more than one processor (program) by using more than one processing unit (processor) at the same time. Multiprocessing is said to be the dynamic allotment of a process or program to one or more than one system in which the one system can involve more than one processor to execute those programs in parallel at the same time.

Head to Head Comparison Between Multithreading vs Multiprocessing (Infographics)

Below are the top 17 differences between Multithreading vs Multiprocessing:

Key Difference Between Multithreading vs Multiprocessing

Let us discuss some of the major key differences between Multithreading vs Multiprocessing:

In a multiprocessing environment, the system is responsible for executing more than one task or process simultaneously, whereas, in multithreading environment, the system is responsible for executing multiple threads which might belong to the same process, simultaneously.
Multiprocessing environment increases the computing-processing (also known as throughput) speed of the system. Multithreading environment increases the responsiveness and utilization of the system.
In a multiprocessing system, CPU switching (according to job scheduling algorithms FCFS, RoundRobin, Preemptive) will take place among multiple programs so it seems that multiple programs are running simultaneously. On other hands, in multithreading system CPU switching will take place among multiple threads that may belong to the same process, to make it possible. So it seems that multiple threads are running simultaneously.
In a multiprocessing system, multiple processes execute concurrently, in a multithreading system multiple threads of single process execute concurrently.
In a multiprocessing system, separate memory and resource are allocated to each of the processes whereas in multithreading system a group of thread belongs to the same process that shares the common memory area and resource.
Multiprocessing systems share the group of computer resources among the number of processes which requires for the execution of different processes simultaneously, like working on eclipse while MS office documentation is running. Whereas in the Multithreading system the execution of the different tasks inside the same process like in MS Word while writing the documentation spell check will take place automatically and printer command can be given while writing the documentation that is known as multithreading.
In multiprocessing system number of process is being executed parallelly whereas in multithreading system components of the same process execute simultaneously.
Multiprocessing system enables forking a process to execute in non-blocking (Deadlock avoidance) mode, assign separate space for its each child process for storing and maintaining code, data and PCB (process control block). whereas multithreading refers to multitasking inside a single process, where child threads/sub thread share the same code and data storage space as its parent thread is using.
Multi Processes systems are heavyweight just because each of the process/tasks require their own separate address space and data space. Interprocess communication and switching from one process to another process ( known as context) is a very expensive operation because they are running in separate addresses and data spaces. Whereas in a multithreading system, threads are lightweight because it is the components of the single process that is being executed and can share the same address and data space and inter-thread communication is not a more expensive operation.
Multithreading does not support objects serialization. Whereas Multiprocessing supports serialization of objects in memory to send it to other processes.
Multiprocessing can be synchronous and asynchronous hence get more work done in less period. On the other hand, multithreading with Less overhead to establish and terminate as compared to process, multithreading environment is not classified.

Multithreading vs Multiprocessing Comparison Table

Let’s discuss the top comparison between Multithreading vs Multiprocessing:

Multithreading	Multiprocessing
Multithreading helps to create multiple threads inside a single process to increase computing throughput.	Basic Multiprocessing helps to increase computing throughput.
Multiple threads of a single process are executed concurrently.	Allows to create and execute multiple processes simultaneously.
CPU has to switch among multiple threads or can execute them simultaneously.	CPU switches among multiple processes simultaneously (according to job scheduling).
Creation of the thread is based on function and it is optimization specific.	Creation of the process depends on the resources.
Threads belonging to the same process share the same memory and resources as that of the process.	Multiprocessing assigned separate memory and resources for each of the processes.
Multithreading systems executes multiple threads of the same simultaneously.	It allows executing multiple programs and tasks.
Multithreading is not divided into categories.	It can be symmetric or asymmetric.
Threads belonging to the same process share the same memory and resources as that of the process.	Multiprocessing allocates separate memory and resources for each process or program.
An average amount of time is taken for job processing.	Takes less time for executing the job/programs.
Execution of thread/child thread is concurrent.	Execution is job/program is concurrent.
The process is divided into several different sub-processes called threads, which have their own way of execution.	Availability of more than one processor per system, which has the ability to execute more than one operation in parallel.
Processing unit can be more than one but not necessary.	System contains more than one processing unit.
Various components of the same process are being executed at a time.	Multiple process can be executed at a time.
Throughput is maximum/optimal.	Throughput is average to less.
Setup of the system is more optimized and less expensive.	Setup of the system is expensive.
Multiple threads are created for the same process, which increases the speed of the execution.	Multiple CPUs are added to the one or multiple systems.
Threads creation from the one-single process is more optimal in terms of efficient execution of the process.	Process creation is a time consuming task.

Conclusion

According to the advantages and the speed of the system in terms if optimization, multithreading can be gradually increased in multiprocessing system, because multithreading in a multiprocessing environment can increase the degree of parallelism and productivity of the system and can make the execution of the operation more efficient and optimal.