RENICE(1) User Commands RENICE(1)


NAME


renice - alter priority of running processes

SYNOPSIS


renice [-n increment] [-i idtype] ID...


renice [-n increment] [-g | -p | -u] ID...


renice priority [-p] pid... [-g gid]... [-p pid]...
[-u user]...


renice priority -g gid... [-g gid]... [-p pid]...
[-u user]...


renice priority -u user... [-g gid]... [-p pid]...
[-u user]...


DESCRIPTION


The renice command alters the scheduling priority of one or more running
processes. By default, the processes to be affected are specified by
their process IDs.


If the first operand is a number within the valid range of priorities
(-20 to 20), renice will treat it as a priority (as in all but the first
synopsis form). Otherwise, renice will treat it as an ID (as in the first
synopsis form).

Altering Process Priority


Users other than the privileged user may only alter the priority of
processes they own, and can only monotonically increase their "nice
value" within the range 0 to 19. This prevents overriding administrative
fiats. The privileged user may alter the priority of any process and set
the priority to any value in the range -20 to 19. Useful priorities are:
19 (the affected processes will run only when nothing else in the system
wants to); 0 (the "base" scheduling priority),; and any negative value
(to make things go very fast). 20 is an acceptable nice value, but will
be rounded down to 19.

OPTIONS


renice supports the following option features:

o The first operand, priority, must precede the options and can
have the appearance of a multi-digit option.

o The -g, -p, and -u options can each take multiple option-
arguments.

o The pid option-argument can be used without its -p option.

o The -i option can be used to specify the ID type for the ID
list. This is preferred in specifying ID type over the use of
the -g | -p | -u syntax, which is now obsolete. See NOTES.


The following options are supported:

-g
Interprets all operands or just the gid arguments as
unsigned decimal integer process group IDs.


-i
This option, together with the ID list arguments,
specifies a class of processes to which the renice
command is to apply. The interpretation of the ID list
depends on the value of idtype. The valid idtype
arguments are: pid, pgid, uid, gid, sid, taskid, projid,
and zoneid.


-n increment
Specifies how the system scheduling priority of the
specified process or processes is to be adjusted. The
increment option-argument is a positive or negative
decimal integer that will be used to modify the system
scheduling priority of the specified process or
processes. Positive increment values cause a lower system
scheduling priority. Negative increment values may
require appropriate privileges and will cause a higher
system scheduling priority.


-p
Interprets all operands or just the pid arguments as
unsigned decimal integer process IDs. The -p option is
the default if no options are specified.


-u
Interprets all operands or just the user argument as
users. If a user exists with a user name equal to the
operand, then the user ID of that user will be used in
further processing. Otherwise, if the operand represents
an unsigned decimal integer, it will be used as the
numeric user ID of the user.


OPERANDS


The following operands are supported:

ID
A process ID, process group ID, or user name/user ID,
depending on the option selected.


priority
The value specified is taken as the actual system scheduling
priority, rather than as an increment to the existing system
scheduling priority. Specifying a scheduling priority higher
than that of the existing process may require appropriate
privileges.


EXAMPLES


Example 1: Adjusting the scheduling priority of process IDs




Adjust the system scheduling priority so that process IDs 987 and 32
would have a lower scheduling priority:


example% renice -n 5 -p 987 32


Example 2: Adjusting the scheduling priority of group IDs




Adjust the system scheduling priority so that group IDs 324 and 76 would
have a higher scheduling priority, if the user has the appropriate
privileges to do so:


example% renice -n -4 -g 324 76


Example 3: Adjusting the scheduling priority of a user ID and user name




Adjust the system scheduling priority so that numeric user ID 8 and user
sas would have a lower scheduling priority:


example% renice -n 4 -u 8 sas


ENVIRONMENT VARIABLES


See environ(7) for descriptions of the following environment variables
that affect the execution of renice: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES,
and NLSPATH.

EXIT STATUS


The following exit values are returned:

0
Successful completion.


>0
An error occurred.


FILES


/etc/passwd
map user names to user IDs


ATTRIBUTES


See attributes(7) for descriptions of the following attributes:


+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+

SEE ALSO


nice(1), passwd(1), priocntl(1), attributes(7), environ(7), standards(7)

NOTES


The renice syntax

renice [-n increment] [-i idtype] ID ...


is preferred over the old syntax

renice [-n increment] [-g | -p| -u] ID ...


which is now obsolete.


If you make the priority very negative, then the process cannot be
interrupted.


To regain control you must make the priority greater than 0.


Users other than the privileged user cannot increase scheduling
priorities of their own processes, even if they were the ones that
decreased the priorities in the first place.


The priocntl command subsumes the function of renice.


January 9, 2004 RENICE(1)