renice(1)
renice --
set system scheduling priorities of running processes
Synopsis
renice [-n .increment.] [-g | -p | -u] .ID . . .
renice nice_value [-p] .pid... [-g gid...][-p pid...][-u user]
renice nice_value -g gid... [-g gid...][-p pid...][-u user]
renice nice_value -u user... [-g gid...][-p pid...][-u user]
Description
The
renice
utility requests that the system scheduling priorities of one or
more running processes be changed.
By default, the applicable processes are specified by their
process IDs.
When a process group is specified (see
-g),
the request applies to all processes in the process group.
If the system scheduling priority of the requested
increment
(or in the older versions of the command, the nice_value)
would raise or lower the system scheduling priority of the executed
utility beyond implementation-dependent limits, then the limit
whose values was exceeded is used.
When a user is
reniced,
the request applies to all processes whose saved set-user-ID matches
the user ID corresponding to the user.
Regardless of which options are supplied or any other factor,
renice
will not alter the system scheduling priorities of any process unless
the user requesting such a change has appropriate privileges to do so
for the specified process.
If the user lacks appropriate privileges to perform the requested action,
the utility will return an error status.
The saved set-user-ID of the user's process will be checked instead of
its effective user ID when
renice
attempts to determine the user ID of the process in order to determine
whether the user has appropriate privileges.
If POSIX2 is set, the standard output is not used; otherwise, the old
and new priority for each affected process is printed to standard output.
renice has the following options:
-g-
Interpret all operands that follow as unsigned decimal integer
process group IDs.
-n increment-
Specify 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.
nice_value-
In the obsolescent version of this command, the first integer is taken
as the actual system scheduling priority to be set, rather than as an
increment to the current priority.
-p-
Interpret all operands that follow as unsigned decimal integer process IDs.
The
-p
option is the default if no options are specified.
-u-
Interpret all operands that follow 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.
ID-
is the process ID, process group ID or user name/user ID, depending
on the option selected.
Environment variables
LANG-
Provide a default value for the internationalization variables
that are unset or null.
If
LANG
is unset or null, the corresponding value from the implementation-specific
default locale will be used.
If any of the internationalization variables contains an invalid
setting, the utility will behave as if none of the variables had
been defined.
LC_ALL-
If set to a non-empty string value, override the values of all the other
internationalization variables.
LC_CTYPE-
Determine the locale for the interpretation of sequences of bytes
of text data as characters (for example, single- as opposed to multi-byte
characters in arguments).
LC_MESSAGES-
Determine the locale that should be used to affect the format and contents
of diagnostic messages written to standard error.
NLSPATH-
Determine the location of message catalogues for the processing
of
LC_MESSAGES.
Examples
Adjust the system scheduling priority so that process IDs 987 and 32
would have a lower scheduling priority:
renice -n 5 -p 987 32
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:
renice -n -4 -g 324 76
Adjust the system scheduling priority so that numeric user ID 8 and user
sas
would have a lower scheduling priority:
renice -n 4 -u 8 sas
Useful nice values on historical systems include 19 or 20
(the affected processes will run only when nothing else in the
system attempts to run), 0 (the base scheduling priority), and any
negative number (to make processes run faster).
References
nice(1)
© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004