renice — alter priority of running processes
renice
priority
[−p
] pid... [−g
] pgrp... [−u
] user...
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. a process group causes all processes in
the process group to have their scheduling priority altered.
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.
The command appeared in BSD4.0
.
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