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Diffstat (limited to 'lib/libc/sys/rtprio.2')
| -rw-r--r-- | lib/libc/sys/rtprio.2 | 199 |
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diff --git a/lib/libc/sys/rtprio.2 b/lib/libc/sys/rtprio.2 new file mode 100644 index 0000000..23088a7 --- /dev/null +++ b/lib/libc/sys/rtprio.2 @@ -0,0 +1,199 @@ +.\"- +.\" Copyright (c) 1994, Henrik Vestergaard Draboel +.\" 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. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by Henrik Vestergaard Draboel. +.\" 4. The name of the author may not be used to endorse or promote products +.\" derived from this software without specific prior written permission. +.\" +.\" 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. +.\"- +.\" 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 December 27, 2011 +.Dt RTPRIO 2 +.Os +.Sh NAME +.Nm rtprio , +.Nm rtprio_thread +.Nd examine or modify realtime or idle priority +.Sh LIBRARY +.Lb libc +.Sh SYNOPSIS +.In sys/types.h +.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, +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 +argument +specifies the operation to be performed. +RTP_LOOKUP to lookup the current priority, +and RTP_SET to set the priority. +.Pp +For the +.Fn rtprio +system call, +the +.Fa pid +argument +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 +argument +is a pointer to a struct rtprio which is used to specify the priority and priority type. +This structure has the following form: +.Bd -literal +struct rtprio { + u_short type; + u_short prio; +}; +.Ed +.Pp +The value of the +.Va type +field may be RTP_PRIO_REALTIME for realtime priorities, +RTP_PRIO_NORMAL for normal priorities, and RTP_PRIO_IDLE for idle priorities. +The priority specified by the +.Va prio +field ranges between 0 and +.Dv RTP_PRIO_MAX +.Pq usually 31 . +0 is the highest possible priority. +.Pp +Realtime and idle priority is inherited through fork() and exec(). +.Pp +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 rtprio_thread +.Sh ERRORS +The +.Fn rtprio +and +.Fn rtprio_thread +system calls +will fail if: +.Bl -tag -width Er +.It Bq Er EFAULT +The rtp pointer passed to +.Fn rtprio +or +.Fn rtprio_thread +was invalid. +.It Bq Er EINVAL +The specified +.Fa prio +was out of range. +.It Bq Er EPERM +The calling thread is not allowed to set the realtime priority. +Only +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 or thread was not found or visible. +.El +.Sh SEE ALSO +.Xr nice 1 , +.Xr ps 1 , +.Xr rtprio 1 , +.Xr setpriority 2 , +.Xr nice 3 , +.Xr renice 8 , +.Xr p_cansee 9 +.Sh AUTHORS +.An -nosplit +The original author was +.An Henrik Vestergaard Draboel Aq Mt hvd@terry.ping.dk . +This implementation in +.Fx +was substantially rewritten by +.An David Greenman . +The +.Fn rtprio_thread +system call was implemented by +.An David Xu . |
