What's the Difference Between Asynchronous Programming and Multithreading?

asynchronous programming and multi -threading: two methods that complement each other

Many developers initially equated the asynchronous programming with multi -thread, thinking that they are the exchanges that allocate tasks to multiple processors. However, if you study carefully, you will find that there are slight but vital differences between the two.

asynchronous method: non -blocking and related to context

Asynchronous method design is used for non -blocking operations. "AWAIT" expression will not stop the current thread during task execution. Instead, it registered the remaining method as a continuation and returns the control to the caller of the asynchronous method.

Interestingly, asynchronous methods do not need to create additional threads. The asynchronous method does not require multiple threads because they run in the current synchronization context and only use thread time during activity. Although "TASK.RUN" can uninstall the CPU dense work to the background thread, it is invalid when waiting for the result.

Multi -threaded: Multi -threaded work

In contrast, multi -threads involve allocating tasks between multiple threads, and each thread has its own special processor. Asynchronous processing tasks, while threads focus on working threads for these tasks. Activities: Asynchronous breakfast

Imagine making breakfast:

Synchronous:

Fry the eggs first, and then bake the bread.

asynchronous single thread:

Start fried eggs and set the timer. Start bake bread and set the timer. During cooking, clean the kitchen. After the timer ring the bell, remove the food and eat it from the fire.
• asynchronous multi -threaded: Hire two chefs, one fried egg, and a grill. Coordinate work to avoid kitchen conflicts and pay the salary of two chefs.
• This analogy indicates that multi -threaded is only a form of asynchronous, where the task is assigned to the work thread (thread). The asynchronous single -threading workflow involves dependency tasks managed by a single work thread.
Jon Skeet's asynchronous example
• Jon Skeet's code demonstrates asynchronous programming:

The execution of this method can be performed in the background without delaying the follow -up operation. It obtains the content of the website, waits to complete, and then display the length.

Enhance the understanding of the workflow

The key to this work process is to understand the way of "AWAIT":

1. Create a new task and request data.
2. Check whether the task has been completed when waiting for the task. If so, get the result and continue to execute.
3. If it is not completed, the remaining method is marked as a continuation, and the control is returned to the caller.
4. After the task is completed, the call is continued on the current thread or another thread.
5. Use the available results to restore execution at the "AWAIT" point.

In essence, asynchronous programming allows you to execute tasks concurrently without blocking or creating additional threads. It is a powerful tool for optimizing performance and maintaining response ability.

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