Multithreading VS Multiprocessing VS Asyncio in Python (80/100 Days of Python)

Martin Mirakyan
3 min readMar 22, 2023

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Day 80 of the “100 Days of Python” blog post series covering threads VS processes VS coroutines

Concurrency is an essential feature in modern software development that allows programs to run multiple tasks simultaneously. Python provides several concurrency techniques, including asyncio, threading, and multiprocessing. Each approach has its own advantages and disadvantages, making it important to understand the differences between them to choose the most suitable technique for your specific use case.

Threading in Python

Threading is a technique where multiple threads of execution run within a single process. Each thread operates independently, allowing the program to perform multiple tasks simultaneously. Python’s threading module provides a simple and easy-to-use interface for creating and managing threads.

One of the main benefits of threading is that it allows for easy data sharing between threads. This can be useful when multiple threads need access to the same resources, such as a database or file system. However, threading has some limitations. Because of the Global Interpreter Lock (GIL), only one thread can execute Python code at a time, making it unsuitable for CPU-bound tasks.

Multiprocessing in Python

Multiprocessing is a technique where multiple processes run independently of each other, with each process having its own memory space. Python’s multiprocessing module provides a simple and easy-to-use interface for creating and managing processes. Unlike threading, multiprocessing is suitable for CPU-bound tasks as it allows the program to take advantage of multiple CPU cores.

However, multiprocessing has some limitations, such as the difficulty in sharing data between processes due to the lack of shared memory. Starting and stopping processes can also be more expensive than starting and stopping threads.

Asynchronous Programming in Python

Asynchronous programming is a technique where a single thread of execution can perform multiple tasks simultaneously. This is achieved using coroutines and an event loop. Python’s asyncio module provides a simple and easy-to-use interface for creating and managing asynchronous tasks.

Asynchronous programming is ideal for I/O-bound tasks as it allows the program to perform other tasks while waiting for I/O operations to complete, making more efficient use of system resources. However, it can be challenging to reason about and predict the order in which tasks will be executed due to coroutines’ suspendability at any time.

Choosing the Right Concurrency Technique for Your Project

Choosing the right concurrency technique for your project depends on the specific use case. Threading is ideal for I/O-bound tasks and data sharing between threads. Multiprocessing is best suited for CPU-bound tasks and taking advantage of multiple CPU cores. Asynchronous programming is perfect for highly concurrent I/O-bound tasks, but it may be difficult to predict the order in which tasks will be executed.

For example, if you need to write a web crawler that fetches data from multiple websites, threading or asynchronous programming might be suitable. In contrast, if you need to perform a computationally intensive task like matrix multiplication, multiprocessing is likely the best option.

What’s next?

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