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 sasENVIRONMENT 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)