Renice
alters the
scheduling priority of one or more running processes.
The following
who
parameters are interpreted as process ID's, process group
ID's, or user names.
Renice 'ing
a process group causes all processes in the process group
to have their scheduling priority altered.
Renice 'ing
a user causes all processes owned by the user to have
their scheduling priority altered.
By default, the processes to be affected are specified by
their process ID's.
Options supported by
renice
-g
Force
who
parameters to be interpreted as process group ID's.
-u
Force the
who
parameters to be interpreted as user names.
-p
Resets the
who
interpretation to be (the default) process ID's.
For example,
renice +1 987 -u daemon root -p 32
would change the priority of process ID's 987 and 32, and
all processes owned by users daemon and root.
Users other than the super-user may only alter the priority of
processes they own,
and can only monotonically increase their ``nice value''
within the range 0 to
PRIO_MAX
(20).
(This prevents overriding administrative fiats.)
The super-user
may alter the priority of any process
and set the priority to any value in the range
PRIO_MIN
(-20)
to
PRIO_MAX
Useful priorities are:
20 (the affected processes will run only when nothing else
in the system wants to),
0 (the ``base'' scheduling priority),
anything negative (to make things go very fast).
Non super-users can not increase scheduling priorities of their own processes,
even if they were the ones that decreased the priorities in the first place.
The Linux kernel (at least version 2.0.0) and linux libc (at least
version 5.2.18) does not agree entirely on what the specifics of the
systemcall interface to set nice values is. Thus causes renice to
report bogus previous nice values.
