Linux nice command
Linux nice command to change over the priority order to execute the program, if the program is not specified, print the current scheduling priority order, a default adjustment is 10, ranging from -20 (highest priority order) to 19 (lowest priority order ).
Access: All users.
grammar
nice [-n adjustment] [-adjustment] [--adjustment=adjustment] [--help] [--version] [command [arg...]]
Parameter Description:
- -n adjustment, -adjustment, --adjustment = adjustment are all the original Priority increase adjustment
- --help show help message
- --version Display version information
Examples
Priority setup runtime
# vi & //后台运行 [1] 15297 # nice vi & //设置默认优先级 [2] 15298 [1]+ Stopped vi # nice -n 19 vi & //设置优先级为19 [3] 15299 [2]+ Stopped nice vi # nice -n -20 vi & //设置优先级为 -20 [4] 15300 [3]+ Stopped nice -n 19 vi # ps -l //显示进程 F S UID PID PPID C PRI NI ADDR SZ WCHAN TTY TIME CMD 4 S 0 15278 15212 0 80 0 - 1208 wait pts/2 00:00:00 bash 0 T 0 15297 15278 0 80 0 - 2687 signal pts/2 00:00:00 vi 0 T 0 15298 15278 0 90 10 - 2687 signal pts/2 00:00:00 vi 0 T 0 15299 15278 1 99 19 - 2687 signal pts/2 00:00:00 vi 4 T 0 15300 15278 3 60 -20 - 2687 signal pts/2 00:00:00 vi 4 R 0 15301 15278 0 80 0 - 625 - pts/2 00:00:00 ps [4]+ Stopped nice -n -20 vi
Priority will be incremented by one and execute ls
nice -n 1 ls
The priority order plus 10 ls and executed
nice ls
Note: Priority (priority) for the operating system used to determine the parameters of CPU allocation, Linux use "turn (round-robin)" CPU scheduling algorithms do, the higher the priority order, CPU time might get it more.