Time of process

system time

CPU Running on the Kernel mode Time for

User time

CPU Running on the User mode Time for

Real time

Process from Start to end The total time of , Include I/O Time ,CPU Time , Process switching And so on .

example

myCp.c

#include <stdio.h>
#include <unistd.h>

int main()
{
    
	int size = 1;
	char buf[size];
	int n = 0;

	while ((n = read(STDIN_FILENO, buf, size)) > 0) {
    
		if (write(STDOUT_FILENO, buf, n) != n) {
    
			printf("write error\n");
			break;
		}
	}

	sleep(1);

	return 0;
}

Running results ：