Several models of IO blocking, non blocking, IO multiplexing, signal driven and asynchronous IO

                        Recommend dark horse redis A network model ,

First of all, understand User status and Kernel mode

        Avoid user applications Lead to conflict even to the extent that Kernel crash , Users' English and kernel should be separated

        According to the addressing control of the process , Divide into two parts ： Kernel mode , User mode

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 1. Blocking io

 2. Non blocking io

        In terms of performance , Although the first stage It's non blocking , But he has to keep asking , It can lead to cpu Idle , Performance degradation

3. Multiplexing io

    High performance , More complicated , It is also commonly used in interviews , Here is a new chapter     https://blog.csdn.net/qq_52252193/article/details/125546614

4. Signal driven IO

 5. asynchronous IO

The whole process is non blocking , The user process completes the asynchronous call , Leave the task to the kernel , The kernel waits for the data to be ready and processed , Then send the results back to the user , （ It's equivalent to the boss letting employees work , The boss is too idle , Employees may die of fatigue ）

  Summary and comparison