What is the difference between swoole process and thread?

Difference: 1. A process is a program running in the system, and a thread belongs to a process. A process can have multiple threads, and threads are the executors of the program; 2. There are no differences between processes. Share any state, and variables can be shared between threads.

The operating environment of this tutorial: Windows10 system, Swoole4 version, DELL G3 computer

What is the difference between swoole process and thread

Process

1. No state is shared between processes

2. The scheduling of processes is completed by the operating system

3.Each process Have its own independent memory space

4. Inter-process communication is mainly achieved through signal transmission. There are many implementation methods, such as semaphores, pipes, events, etc. The communication efficiency of any method is It needs to go through the kernel, resulting in relatively low communication efficiency.

5. Since it is an independent memory space, when context switching, it is necessary to save the information of the first call stack, the information of each CPU register, virtual memory, and open related handles. and other information, so switching between context processes is very expensive and communication is troublesome.

Threads

1. Sharing variables between threads solves the problem of troublesome communication. Access to variables requires locks

2. One process can It has multiple threads, but each thread will share the resources requested by the operating system from the parent process. This includes virtual memory, files, etc. Since it is a shared resource, the system resource usage required to create a thread is much smaller than that of a process. Accordingly, it can The number of threads created has also become relatively much larger.

3. In addition, in terms of scheduling, because the memory is shared, there are fewer things that need to be saved when context switching, so that context switching becomes efficient.

What is a process?

A process is a program that is running in the system. Once the program is running, it is a process.

A process can be seen as an instance of program execution.

Tags: One process cannot access the variables and data structures of another process. If you want one process to access the resources of another process, you need to use inter-process communication, such as pipes, files, sockets, etc.

What is a thread?

Threads belong to processes and are the executors of programs.

A process contains at least one main thread, and can also have more sub-threads. Each thread uses the stack space of the process to which it belongs.

A thread is an entity of the process and an execution path of the process.

Tags: Multiple threads in the same process will share part of the state, and multiple threads can read and write the same memory.

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