SCHED_SETPARAM
Section: POSIX Programmer's Manual (3P)
Updated: 2013
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PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
NAME
sched_setparam
--- set scheduling parameters
(
REALTIME)
SYNOPSIS
#include <sched.h>
int sched_setparam(pid_t pid, const struct sched_param *param);
DESCRIPTION
The
sched_setparam()
function shall set the scheduling parameters of the process specified by
pid
to the values specified by the
sched_param
structure pointed to by
param.
The value of the
sched_priority
member in the
sched_param
structure shall be any integer within the inclusive priority range for
the current scheduling policy of the process specified by
pid.
Higher numerical values for the priority represent higher priorities.
If the value of
pid
is negative, the behavior of the
sched_setparam()
function is unspecified.
If a process specified by
pid
exists, and if the calling process has permission, the scheduling
parameters shall be set for the process whose process ID is equal to
pid.
If
pid
is zero, the scheduling parameters shall be set for the calling process.
The conditions under which one process has permission to change the
scheduling parameters of another process are implementation-defined.
Implementations may require the requesting process to have appropriate
privileges to set its own scheduling parameters or those of another
process.
See
Scheduling Policies
for a description on how this function affects the scheduling of
the threads within the target process.
If the current scheduling policy for the target process is not
SCHED_FIFO, SCHED_RR,
or SCHED_SPORADIC,
the result is implementation-defined; this case includes the
SCHED_OTHER policy.
The specified
sched_ss_repl_period
shall be greater than or equal to the specified
sched_ss_init_budget
for the function to succeed; if it is not, then the function shall
fail.
The value of
sched_ss_max_repl
shall be within the inclusive range [1,{SS_REPL_MAX}] for the function
to succeed; if not, the function shall fail. It is unspecified whether the
sched_ss_repl_period
and
sched_ss_init_budget
values are stored as provided by this function or are rounded to
align with the resolution of the clock being used.
This function is not atomic with respect to other threads in the
process. Threads may continue to execute while this function call is in
the process of changing the scheduling policy for the underlying
kernel-scheduled entities used by the process contention scope
threads.
RETURN VALUE
If successful, the
sched_setparam()
function shall return zero.
If the call to
sched_setparam()
is unsuccessful, the priority shall remain unchanged, and the function
shall return a value of -1 and set
errno
to indicate the error.
ERRORS
The
sched_setparam()
function shall fail if:
- EINVAL
-
One or more of the requested scheduling parameters is outside the range
defined for the scheduling policy of the specified
pid.
- EPERM
-
The requesting process does not have permission to set the scheduling
parameters for the specified process, or does not have appropriate
privileges to invoke
sched_setparam().
- ESRCH
-
No process can be found corresponding to that specified by
pid.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
Scheduling Policies,
sched_getparam(),
sched_getscheduler(),
sched_setscheduler()
The Base Definitions volume of POSIX.1-2008,
<sched.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.unix.org/online.html .
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
Index
- PROLOG
-
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- EXAMPLES
-
- APPLICATION USAGE
-
- RATIONALE
-
- FUTURE DIRECTIONS
-
- SEE ALSO
-
- COPYRIGHT
-
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