nice(2)
NAME
nice − set program priority
SYNTAX
int nice(incr)
int incr;
DESCRIPTION
The nice system call increases the scheduling priority of the process as specified by incr. Positive priorities get less service than normal. Priority 10 is recommended to users who wish to execute long-running programs.
A maximum nice value of 39 and a minimum nice value of 0 are imposed by the system. Requests for values above or below these limits result in the nice value being set to the corresponding limit.
Negative increments are ignored, except on behalf of the superuser. The priority is limited to the range −20 (most urgent) to 20 (least).
The priority of a process is passed to a child process by the fork call. For a privileged process to return to normal priority from an unknown state, nice should be called successively with arguments −40 (goes to priority −20 because of truncation), 20 (to get to 0), then 0 (to maintain compatibility with previous versions of this call).
DIAGNOSTICS
The nice call will fail if:
[EPERM] The specified incr is negative, and the process’s effective user ID is not the superuser.
ASSEMBLER
(nice = 34.)
(priority in r0)
sys nice