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authorXin LI <delphij@FreeBSD.org>2011-12-27 10:34:00 +0000
committerXin LI <delphij@FreeBSD.org>2011-12-27 10:34:00 +0000
commitb0266169d4f5f1e4434a9304bf1c0bc6f29665ee (patch)
tree168d2d780271b447bad93e9526ebb8575ff82a08 /lib/libc/sys/rtprio.2
parent436c93525d84b18ed0aed75a060e3fdf101eff51 (diff)
downloadsrc-b0266169d4f5f1e4434a9304bf1c0bc6f29665ee.tar.gz
src-b0266169d4f5f1e4434a9304bf1c0bc6f29665ee.zip
Update rtprio(2) manual page to reflect the latest changes in -CURRENT as
well as provide documentation for rtprio_thread(2) system call. MFC after: 1 month X-MFC-after: r228470
Notes
Notes: svn path=/head/; revision=228910
Diffstat (limited to 'lib/libc/sys/rtprio.2')
-rw-r--r--lib/libc/sys/rtprio.298
1 files changed, 81 insertions, 17 deletions
diff --git a/lib/libc/sys/rtprio.2 b/lib/libc/sys/rtprio.2
index afed81e2d98c..faad9417c55c 100644
--- a/lib/libc/sys/rtprio.2
+++ b/lib/libc/sys/rtprio.2
@@ -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 .