247 lines
6.9 KiB
Groff
247 lines
6.9 KiB
Groff
.\" $NetBSD: sched.3,v 1.1 2008/03/10 14:47:06 rmind Exp $
|
|
.\"
|
|
.\" Copyright (c) 2008 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by Mindaugas Rasiukevicius <rmind at NetBSD org>.
|
|
.\"
|
|
.\" 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 the NetBSD
|
|
.\" Foundation, Inc. and its contributors.
|
|
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
|
|
.\" contributors may be used to endorse or promote products derived
|
|
.\" from this software without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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 March 10, 2008
|
|
.Dt SCHED 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm sched_setparam ,
|
|
.Nm sched_getparam ,
|
|
.Nm sched_setscheduler ,
|
|
.Nm sched_getscheduler ,
|
|
.Nm sched_get_priority_max ,
|
|
.Nm sched_get_priority_min ,
|
|
.Nm sched_rr_get_interval ,
|
|
.Nm sched_yield
|
|
.Nd process scheduling
|
|
.Sh LIBRARY
|
|
.Lb librt
|
|
.Sh SYNOPSIS
|
|
.In 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"
|
|
.Ft int
|
|
.Fn sched_setscheduler "pid_t pid" "int policy" "const struct sched_param *param"
|
|
.Ft int
|
|
.Fn sched_getscheduler "pid_t pid"
|
|
.Ft int
|
|
.Fn sched_get_priority_max "int policy"
|
|
.Ft int
|
|
.Fn sched_get_priority_min "int policy"
|
|
.Ft int
|
|
.Fn sched_rr_get_interval "pid_t pid" "struct timespec *interval"
|
|
.Ft int
|
|
.Fn sched_yield "void"
|
|
.Sh DESCRIPTION
|
|
This section describes the functions used to get the scheduling
|
|
information about the processes, and control the scheduling of the process.
|
|
.Pp
|
|
Available scheduling policies (classes) are:
|
|
.Bl -tag -width SCHED_OTHER
|
|
.It Dv SCHED_OTHER
|
|
Time-sharing (TS) scheduling policy.
|
|
The default policy in
|
|
.Nx .
|
|
.It Dv SCHED_FIFO
|
|
First in, first out (FIFO) scheduling policy.
|
|
.It Dv SCHED_RR
|
|
Round robin scheduling policy.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fa struct sched_param
|
|
contains at least one member:
|
|
.Bl -tag -width flags
|
|
.It Fa sched_priority
|
|
Specifies the priority of the process.
|
|
.El
|
|
.Ss FUNCTIONS
|
|
.Bl -tag -width compact
|
|
.It Fn sched_setparam pid param
|
|
Sets the scheduling parameters for the process specified by
|
|
.Fa pid
|
|
to
|
|
.Fa param .
|
|
If the value of
|
|
.Fa pid
|
|
is equal to zero, then the calling process is used.
|
|
.It Fn sched_getparam pid param
|
|
Gets the scheduling parameters of the process specified by
|
|
.Fa pid
|
|
into the structure
|
|
.Fa param .
|
|
If the value of
|
|
.Fa pid
|
|
is equal to zero, then the calling process is used.
|
|
.It Fn sched_setscheduler pid policy param
|
|
Set the scheduling policy and parameters for the process specified by
|
|
.Fa pid .
|
|
If the value of
|
|
.Fa pid
|
|
is equal to zero, then the calling process is used.
|
|
.It Fn sched_getscheduler pid
|
|
Returns the scheduling policy of the process specified by
|
|
.Fa pid .
|
|
If the value of
|
|
.Fa pid
|
|
is equal to zero, then the calling process is used.
|
|
.It Fn sched_get_priority_max policy
|
|
Returns the maximal priority which may be used for the scheduling policy
|
|
specified by
|
|
.Fa policy .
|
|
.It Fn sched_get_priority_min policy
|
|
Returns the minimal priority which may be used for the scheduling policy
|
|
specified by
|
|
.Fa policy .
|
|
.It Fn sched_rr_get_interval pid interval
|
|
Returns the time quantum into the structure
|
|
.Fa interval
|
|
of the process specified by
|
|
.Fa pid .
|
|
If the value of
|
|
.Fa pid
|
|
is equal to zero, then the calling process is used.
|
|
The process must be running at
|
|
.Fa SCHED_RR
|
|
scheduling policy.
|
|
.It Fn sched_yield
|
|
Yields a processor voluntarily and gives other threads a chance to run
|
|
without waiting for an involuntary preemptive switch.
|
|
.El
|
|
.Sh RETURN VALUES
|
|
.Fn sched_setparam ,
|
|
.Fn sched_getparam ,
|
|
.Fn sched_rr_get_interval ,
|
|
and
|
|
.Fn sched_yield
|
|
return 0 on success.
|
|
Otherwise, \-1 is returned and
|
|
.Va errno
|
|
is set to indicate the error.
|
|
.Pp
|
|
.Fn sched_setscheduler
|
|
returns the previously used scheduling policy on success.
|
|
Otherwise, \-1 is returned and
|
|
.Va errno
|
|
is set to indicate the error.
|
|
.Pp
|
|
.Fn sched_getscheduler
|
|
returns the scheduling policy on success.
|
|
Otherwise, \-1 is returned and
|
|
.Va errno
|
|
is set to indicate the error.
|
|
.Pp
|
|
The
|
|
.Fn sched_get_priority_max
|
|
and
|
|
.Fn sched_get_priority_min
|
|
return the maximal/minimal priority value on success.
|
|
Otherwise, \-1 is returned and
|
|
.Va errno
|
|
is set to indicate the error.
|
|
.Sh ERRORS
|
|
The
|
|
.Fn sched_setparam
|
|
and
|
|
.Fn sched_setscheduler
|
|
functions fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
At least one of the specified scheduling parameters was invalid.
|
|
.It Bq Er EPERM
|
|
The calling process has no appropriate privileges to perform the operation.
|
|
.It Bq Er ESRCH
|
|
No process can be found corresponding to that specified by
|
|
.Fa pid ,
|
|
and value of
|
|
.Fa pid
|
|
is not zero.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn sched_getparam
|
|
and
|
|
.Fn sched_getscheduler
|
|
functions fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EPERM
|
|
The calling process is not a super-user and its effective user id does not
|
|
match the effective user-id of the specified process.
|
|
.It Bq Er ESRCH
|
|
No process can be found corresponding to that specified by
|
|
.Fa pid ,
|
|
and value of
|
|
.Fa pid
|
|
is not zero.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn sched_get_priority_max
|
|
and
|
|
.Fn sched_get_priority_min
|
|
functions fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EINVAL
|
|
The specified scheduling policy is invalid.
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fn sched_rr_get_interval
|
|
function fails if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ESRCH
|
|
No process can be found corresponding to that specified by
|
|
.Fa pid ,
|
|
and value of
|
|
.Fa pid
|
|
is not zero.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr pset 3 ,
|
|
.Xr schedctl 8
|
|
.Sh STANDARDS
|
|
These functions conform to
|
|
.St -p1003.1-2001
|
|
standard.
|
|
.Sh HISTORY
|
|
The scheduling functions appeared in
|
|
.Nx 5.0 .
|
|
.Sh BUGS
|
|
Currently, these functions are valid and work correctly only with the
|
|
SCHED_M2 thread scheduler implementation.
|