diff options
Diffstat (limited to 'lib/libc/sys/sched_setparam.2')
-rw-r--r-- | lib/libc/sys/sched_setparam.2 | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/lib/libc/sys/sched_setparam.2 b/lib/libc/sys/sched_setparam.2 new file mode 100644 index 0000000..b627e69 --- /dev/null +++ b/lib/libc/sys/sched_setparam.2 @@ -0,0 +1,172 @@ +.\" $FreeBSD$ +.\" Copyright (c) 1998 HD Associates, Inc. +.\" 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. +.\" +.Dd Mar 12, 1998 +.Dt SCHED_SETPARAM 2 +.Os BSD 4 +.Sh NAME +.Nm sched_setparam , +.Nm sched_getparam +.Nd set/get scheduling parameters +.Sh SYNOPSIS +.Fd #include <sched.h> +.Ft int +.Fn sched_setparam "pid_t pid" "const struct sched_param *param" +.Ft int +.Fn sched_getparam "pid_t pid" "struct sched_param *param" +.Sh DESCRIPTION +The +.Fn sched_setparam +function sets the scheduling parameters of the process specified by +.Fa pid +to the values specified by the +.Fa sched_param +structure pointed to by +.Fa param . +The value of the +.Fa sched_priority +member in the +.Fa param +structure must be any integer within the inclusive priority range for +the current scheduling policy of the process specified by +.Fa pid . +Higher numerical values for the priority represent higher priorities. +.Pp +In this implementation, if the value of +.Fa pid +is negative the function will fail. +.Pp +If a process specified by +.Fa pid +exists and if the calling process has permission, the scheduling +parameters are set for the process whose process ID is equal to +.Fa pid . +.Pp +If +.Fa pid +is zero, the scheduling parameters are set for the calling process. +.Pp +In this implementation, the policy of when a process can affect +the scheduling parameters of another process is specified in +.Xr p1003_1b +as a write-style operation. +.Pp +The target process, whether it is running or not running, will resume +execution after all other runnable processes of equal or greater +priority have been scheduled to run. +.Pp +If the priority of the process specified by the +.Fa pid +argument is set higher than that of the lowest priority running process +and if the specified process is ready to run, the process specified by +the +.Fa pid +argument will preempt a lowest priority running process. Similarly, if +the process calling +.Fn sched_setparam +sets its own priority lower than that of one or more other nonempty +process lists, then the process that is the head of the highest priority +list will also preempt the calling process. Thus, in either case, the +originating process might not receive notification of the completion of +the requested priority change until the higher priority process has +executed. +.Pp +In this implementation, when the current scheduling policy for the +process specified by +.Fa pid +is normal timesharing (SCHED_OTHER, aka SCHED_NORMAL when not POSIX-source) +or the idle policy (SCHED_IDLE when not POSIX-source) then the behavior +is as if the process had been running under SCHED_RR with a priority +lower than any actual realtime priority. +.Pp +The +.Fn sched_getparam +function will return the scheduling parameters of a process specified +by +.Fa pid +in the +.Fa sched_param +structure pointed to by +.Fa param . +.Pp +If a process specified by +.Fa pid +exists and if the calling process has permission, +the scheduling parameters for the process whose process ID is equal to +.Fa pid +are returned. +.Pp +In this implementation, the policy of when a process can obtain the +scheduling parameters of another process are detailed in +.Xr p1003_1b +as a read-style operation. +.Pp +If +.Fa pid +is zero, the scheduling parameters for the calling process will be +returned. In this implementation, the +.Fa sched_getparam +function will fail if +.Fa pid +is negative. +.Sh RETURN +The function will return zero if it completes successfully, or it +will return a value of -1 and set +.Va errno +to indicate the error. +.Sh ERRORS +On failure +.Va errno +will be set to the corresponding value: +.Bl -tag -width [EFAULT] +.It Bq Er ENOSYS +The system is not configured to support this functionality. +.It Bq Er EPERM +The requesting process doesn not have permission as detailed in +.Xr p1003_1b . +.It Bq Er ESRCH +No process can be found corresponding to that specified by +.Fa pid . +.It Bq Er EINVAL +For +.Fn sched_setparam : +one or more of the requested scheduling parameters +is outside the range defined for the scheduling policy of the specified +.Fa pid . +.El +.Sh SEE ALSO +.Xr sched_get_priority_max 2 , +.Xr sched_get_priority_min 2 , +.Xr sched_getscheduler 2 , +.Xr sched_rr_get_interval 2 , +.Xr sched_setscheduler 2 , +.Xr sched_yield 2 +.Sh STANDARDS +The +.Fn sched_setparam +and +.Fn sched_getparam +functions conform to +.St -p1003.1b-93 . |