Multi-process and multi-thread
Process basis
Processes and procedures
What is a program ?
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Ordered collection of instructions and data
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Generalized problem-solving logic set
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An executable binary file in a narrow sense
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Is a static concept
What is a process?
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The program runs as a process
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When the program is executed once, a process is generated. When the execution ends, the process ends
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Process is the smallest unit of operating system allocation of resourcesAllocate memory, files. . .
Thread
Thread is the smallest unit of CPU scheduling
A process can contain several threads, at least one
The relationship between program and process
Procedure—>Recipe
Process—"A dish
A program can spawn multiple processes
Parallel and concurrency
| Serial number | Happening | the difference |
|---|---|---|
| parallel | Multiple processes or multiple threads | Multi-core, multiple CPU |
| Concurrent | Multiple processes or multiple threads | Single core |
Single process
Concurrent
Because the switching is fast, there is an illusion of simultaneous execution
Parallel
Multi-core and multiple CPUs to achieve true simultaneous execution