1130b656e5
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
107 lines
3.9 KiB
Groff
107 lines
3.9 KiB
Groff
.\" Copyright (c) 1994, Henrik Vestergaard Draboel
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by Henrik Vestergaard Draboel.
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.\" 4. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 23, 1994
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.Dt RTPRIO 2
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.Sh NAME
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.Nm rtprio
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.Nd examine or modify a process realtime or idle priority
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.Sh SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <sys/rtprio.h>
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.Ft int
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.Fn rtprio "int function" "pid_t pid" "struct rtprio *rtp"
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.Sh DESCRIPTION
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.Fn rtprio
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is used to lookup or change the realtime or idle priority of a process.
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.Fa function
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specifies the operation to be performed. RTP_LOOKUP to lookup the current priority,
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and RTP_SET to set the priority.
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.Fa pid
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specifies the process to be used, 0 for the current process.
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.Fa *rtp
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is a pointer to a struct rtprio which is used to specify the priority and priority type.
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This structure has the following form:
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.Bd -literal
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struct rtprio {
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u_short type;
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u_short prio;
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};
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.Ed
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.Pp
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The value of the
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.Nm type
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field may be RTP_PRIO_REALTIME for realtime priorities,
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RTP_PRIO_NORMAL for normal priorities, and RTP_PRIO_IDLE for idle priorities.
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The priority specified by the
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.Nm prio
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field ranges between 0 and
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.Dv RTP_PRIO_MAX (usually 31) .
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0 is the highest possible priority.
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Realtime and idle priority is inherited through fork() and exec().
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A realtime process can only be preempted by a process of equal or
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higher priority, or by an interrupt; idle priority processes will run only
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when no other real/normal priority process is runnable. Higher real/idle priority processes
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preempt lower real/idle priority processes. Processes of equal real/idle priority are run round-robin.
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.Sh RETURN VALUES
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.Fn rtprio
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will return 0 for success and -1 for all errors. The global variable
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.Va errno
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will be set to indicate the error.
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.Sh ERRORS
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.Fn rtprio
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will fail if
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.Bl -tag -width Er
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.It Bq Er EINVAL
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The specified
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.Fa prio
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was out of range.
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.It Bq Er EPERM
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The calling process is not allowed to set the realtime priority. Only
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root is allowed to change the realtime priority of any process, and non-root
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may only change the idle priority of the current process.
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.It Bq Er ESRCH
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The specified process was not found.
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.Sh AUTHOR
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The original author was Henrik Vestergaard Draboel - hvd@terry.ping.dk. This
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implementation in FreeBSD was substantially rewritten by David Greenman.
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.Sh SEE ALSO
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.Xr rtprio 1 ,
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.Xr nice 1 ,
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.Xr ps 1 ,
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.Xr setpriority 2 ,
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.Xr nice 3 ,
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.Xr renice 8
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