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Update rtprio(2) manual page to reflect the latest changes in -CURRENT as

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well as provide documentation for rtprio_thread(2) system call.

MFC after:	1 month
X-MFC-after:	r228470
This commit is contained in:
Xin LI 2011-12-27 10:34:00 +00:00
parent 436c93525d
commit b0266169d4
2 changed files with 82 additions and 17 deletions
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1
lib/libc/sys/Makefile.inc
View File

@ -188,6 +188,7 @@ MLINKS+=read.2 pread.2 read.2 preadv.2 read.2 readv.2
MLINKS+=readlink.2 readlinkat.2
MLINKS+=recv.2 recvfrom.2 recv.2 recvmsg.2
MLINKS+=rename.2 renameat.2
MLINKS+=rtprio.2 rtprio_thread.2
.if !defined(NO_P1003_1B)
MLINKS+=sched_get_priority_max.2 sched_get_priority_min.2 \
sched_get_priority_max.2 sched_rr_get_interval.2

98
lib/libc/sys/rtprio.2
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@ -1,3 +1,4 @@
.\"-
.\" Copyright (c) 1994, Henrik Vestergaard Draboel
.\" All rights reserved.
.\"
@ -26,15 +27,40 @@
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"-
.\" Copyright (c) 2011 Xin LI <delphij@FreeBSD.org>
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd July 23, 1994
.Dd December 27, 2011
.Dt RTPRIO 2
.Os
.Sh NAME
.Nm rtprio
.Nd examine or modify a process realtime or idle priority
.Nm rtprio ,
.Nm rtprio_thread
.Nd examine or modify realtime or idle priority
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
@ -42,11 +68,18 @@
.In sys/rtprio.h
.Ft int
.Fn rtprio "int function" "pid_t pid" "struct rtprio *rtp"
.Ft int
.Fn rtprio_thread "int function" "lwpid_t lwpid" "struct rtprio *rtp"
.Sh DESCRIPTION
The
.Fn rtprio
system call
is used to lookup or change the realtime or idle priority of a process.
is used to lookup or change the realtime or idle priority of a process,
or the calling thread.
The
.Fn rtprio_thread
system call
is used to lookup or change the realtime or idle priority of a thread.
.Pp
The
.Fa function
@ -54,10 +87,31 @@ argument
specifies the operation to be performed.
RTP_LOOKUP to lookup the current priority,
and RTP_SET to set the priority.
The
.Pp
For the
.Fn rtprio
system call,
the
.Fa pid
argument
specifies the process to be used, 0 for the current process.
specifies the process to operate on,
0 for the calling thread.
When
.Fa pid
is non-zero,
the system call reports the highest priority in the process,
or sets all threads' priority in the process,
depending on value of the
.Fa function
argument.
.Pp
For the
.Fn rtprio_thread
system call,
the
.Fa lwpid
specifies the thread to operate on,
0 for the calling thread.
.Pp
The
.Fa *rtp
@ -83,12 +137,12 @@ field ranges between 0 and
.Pp
Realtime and idle priority is inherited through fork() and exec().
.Pp
A realtime process can only be preempted by a process of equal or
higher priority, or by an interrupt; idle priority processes will run only
when no other real/normal priority process is runnable.
Higher real/idle priority processes
preempt lower real/idle priority processes.
Processes of equal real/idle priority are run round-robin.
A realtime thread can only be preempted by a thread of equal or
higher priority, or by an interrupt; idle priority threads will run only
when no other real/normal priority thread is runnable.
Higher real/idle priority threads
preempt lower real/idle priority threads.
Threads of equal real/idle priority are run round-robin.
.Sh RETURN VALUES
.Rv -std rtprio
.Sh ERRORS
@ -102,12 +156,17 @@ The specified
.Fa prio
was out of range.
.It Bq Er EPERM
The calling process is not allowed to set the realtime priority.
The calling thread is not allowed to set the realtime priority.
Only
root is allowed to change the realtime priority of any process, and non-root
may only change the idle priority of the current process.
root is allowed to change the realtime priority of any thread, and non-root
may only change the idle priority of threads the user owns,
when the
.Xr sysctl 8
variable
.Va security.bsd.unprivileged_idprio
is set to non-zero.
.It Bq Er ESRCH
The specified process was not found.
The specified process or thread was not found or visible.
.El
.Sh SEE ALSO
.Xr nice 1 ,
@ -115,7 +174,8 @@ The specified process was not found.
.Xr rtprio 1 ,
.Xr setpriority 2 ,
.Xr nice 3 ,
.Xr renice 8
.Xr renice 8 ,
.Xr p_cansee 9 .
.Sh AUTHORS
.An -nosplit
The original author was
@ -124,3 +184,7 @@ This implementation in
.Fx
was substantially rewritten by
.An David Greenman .
The
.Fn rtprio_thread
system call was implemented by
.An David Xu .