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Diffstat (limited to 'lib/libc/sys/rtprio.2')
-rw-r--r-- | lib/libc/sys/rtprio.2 | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/lib/libc/sys/rtprio.2 b/lib/libc/sys/rtprio.2 new file mode 100644 index 0000000..c9957fd --- /dev/null +++ b/lib/libc/sys/rtprio.2 @@ -0,0 +1,106 @@ +.\" 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. +.\" +.\" $Id: $ +.\" +.Dd July 23, 1994 +.Dt RTPRIO 2 +.Sh NAME +.Nm rtprio +.Nd examine or modify a process realtime or idle priority +.Sh SYNOPSIS +.Fd #include <sys/resource.h> +.Fd #include <sys/rtprio.h> +.Ft int +.Fn rtprio "function" "pid_t pid" "struct rtprio *rtp" +.Sh DESCRIPTION +.Fn rtprio +is used to lookup or change the realtime or idle priority of a process. + +.Fa function +specifies the operation to be performed. RTP_LOOKUP to lookup the current priority, +and RTP_SET to set the priority. +.Fa pid +specifies the process to be used, 0 for the current process. + +.Fa *rtp +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 +.Nm 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 +.Nm prio +field ranges between 0 and +.Dv RTP_PRIO_MAX (usually 31) . +0 is the highest possible priority. + +Realtime and idle priority is inherited through fork() and exec(). + +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. +.Sh RETURN VALUES +.Fn rtprio +will return 0 for success and -1 for all errors. The global variable +.Va errno +will be set to indicate the error. +.Sh ERRORS +.Fn rtprio +will fail if +.Bl -tag -width Er +.It Bq Er EINVAL +The specified +.Fa prio +was out of range. +.It Bq Er EPERM +The calling process 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. +.It Bq Er ESRCH +The specified process was not found. +.Sh AUTHOR +The original author was Henrik Vestergaard Draboel - hvd@terry.ping.dk. This +implementation in FreeBSD was substantially rewritten by David Greenman. +.Sh SEE ALSO +.Xr rtprio 1 , +.Xr nice 1 , +.Xr ps 1 , +.Xr nice 2 , +.Xr renice 8 + |