Difference between process and thread

 process ：
 An application that runs in memory .
 Each process has its own independent memory space , A process can have multiple threads .

 Threads ：
 An execution task in the process （ control unit ）, Responsible for the execution of programs in the current process .
 A process has at least one thread , A process can run multiple threads , Multiple threads can share data .

Fundamental difference ： Processes are performed by the operating system Resource allocation The basic unit of , Thread is Independent scheduling The basic unit of .

address space ： Process includes Independent address space , Threads do not have their own independent address space , it Share the space of the owning process .

resources ： When the system is running Allocate resources for each process , Instead of allocating resources to threads , The resource used by a thread comes from the resource of the process it belongs to .

expenses ： Between processes Switching costs a lot , Switching between threads The cost is relatively small ; Creating a thread costs less than a process .

signal communication ： Interthread communication Communication between processes More convenient .

Inclusion relation ： Thread is A lightweight process , It's part of the process .

Influence relationships ： One After the process crashes , In protected mode No impact on other processes , however One thread crashes and the whole process dies . So multiprocessing is more robust than multithreading .