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 priori-
ties are: 19 (the affected processes will run only when
nothing else in the system wants to); 0 (the "base" schedul-
ing 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 argu-
ments are: pid, pgid, uid, gid, sid, taskid, and pro-
jid.
-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(5) 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(5) for descriptions of the following attri-
butes:
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
SEE ALSO
nice(1), passwd(1), priocntl(1), attributes(5), environ(5),
standards(5)
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.
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