Table of contents
(1) The simplest thread implementation (user-level thread)
(3) Kernel + user (one-to-one, many-to-one, many-to-many)
5. Thread conversion (state transition)
6. Thread parameter indicators
7. Disadvantages of each thread (user thread, kernel thread, lightweight process)
2. Chapter 2 - [Thread]
1. The concept of thread
| Thread ( Thread ) |
Process ( Process ) |
|
| concept |
The smallest unit of program execution is an execution path in the process |
The program instance being executed has independent memory space and resources |
| the difference |
Share the address space and resources of the same process |
Have independent address space and resources |
| Lightweight, the overhead of creating and destroying threads is small |
Heavyweight, the overhead of creating and destroying processes is relatively large |
|
| Less overhead for switching between threads |
The overhead of switching between processes is large |
|
| advantage |
Resource sharing, high communication efficiency |
Good isolation, a process crash will not affect other processes |
| High concurrency, can make full use of the computing power of multi-core processors |
Can make full use of the computing power of multiple machines to realize distributed computing |
|
| shortcoming |
Sharing data between threads is prone to race conditions |
Context switching is expensive |
| Errors can affect the entire process |
More resource usage |
|
| Application Scenario |
Concurrent processing, improve program performance |
Multitasking, system-level tasks, distributed computing, containerized applications, etc. |
2. Properties of threads
3. Implementation of threads
(1) The simplest thread implementation (user-level thread)
Use a [while loop] + [if judgment] to achieve
(2) Kernel-level threads
(3) Kernel + user (one-to-one, many-to-one, many-to-many)
(4) Summary
5. Thread conversion (state transition)
6. Thread parameter indicators
7. Disadvantages of each thread (user thread, kernel thread, lightweight process)
Today, I just use it to relax, but the relaxation is for better study later, come on!