renice.8

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)renice.8	8.1	9/11/90
.TH renice 8
.SH Name
renice \- alter priority of running processes
.SH Syntax
.B /etc/renice
priority [ [
.B \-p
] pid ... ] [ [
.B \-g
] pgrp ... ] [ [
.B \-u
] user ... ]
.SH Description
.NXR "renice command"
.NXAM "getpriority system call" "renice command"
.NXR "process" "changing priority of running"
The 
.PN renice
command alters the 
scheduling priority of one or more running processes.
The
.I who
parameters are interpreted as process ID's, process group
ID's, or user names.
Using
.PN renice
on a process group causes all processes in the process group
to have their scheduling priority altered.  
Using
.PN renice
on 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.  
.SH Options
To force 
.I who
parameters to be interpreted as process group ID's, a
.PN \-g 
may be specified.  To force the
.I who
parameters to be interpreted as user names, a
.PN \-u
may be given.  Supplying
.PN \-p
will reset 
.I who
interpretation to be (the default) process ID's.
.PP
Users other than the superuser may only alter the priority of
processes they own,
and can only monotonically increase their ``nice value''
within the range 0 to PRIO_MIN (20).
(This prevents overriding administrative fiats.)
The superuser can alter the priority of any process
and set the priority to any value in the range PRIO_MAX (\-20)
to PRIO_MIN.
Useful priorities are:
19 (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).
.SH Examples
The following command
changes the priority of process ID's 987 and 32, and
all processes owned by users daemon and root:
.EX
/etc/renice +1 987 \-u daemon root \-p 32 
.EE
.SH Restrictions
If you make the priority very negative,
then the process cannot be interrupted.
To regain control you make the priority greater than zero.
Non-superusers cannot increase scheduling priorities of 
their own processes, even if they were the ones that 
decreased the priorities in the first place.
.SH Files
.TP 15
.PN /etc/passwd
Maps user names to user IDs
.SH See Also
getpriority(2), setpriority(2)