pthread_getschedparam(3p) — Linux manual page



PROLOG         top

       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         top

       pthread_getschedparam, pthread_setschedparam — dynamic thread
       scheduling parameters access (REALTIME THREADS)

SYNOPSIS         top

       #include <pthread.h>

       int pthread_getschedparam(pthread_t thread, int *restrict policy,
           struct sched_param *restrict param);
       int pthread_setschedparam(pthread_t thread, int policy,
           const struct sched_param *param);

DESCRIPTION         top

       The pthread_getschedparam() and pthread_setschedparam() functions
       shall, respectively, get and set the scheduling policy and
       parameters of individual threads within a multi-threaded process
       to be retrieved and set. For SCHED_FIFO and SCHED_RR, the only
       required member of the sched_param structure is the priority
       sched_priority.  For SCHED_OTHER, the affected scheduling
       parameters are implementation-defined.

       The pthread_getschedparam() function shall retrieve the
       scheduling policy and scheduling parameters for the thread whose
       thread ID is given by thread and shall store those values in
       policy and param, respectively. The priority value returned from
       pthread_getschedparam() shall be the value specified by the most
       recent pthread_setschedparam(), pthread_setschedprio(), or
       pthread_create() call affecting the target thread. It shall not
       reflect any temporary adjustments to its priority as a result of
       any priority inheritance or ceiling functions. The
       pthread_setschedparam() function shall set the scheduling policy
       and associated scheduling parameters for the thread whose thread
       ID is given by thread to the policy and associated parameters
       provided in policy and param, respectively.

       The policy parameter may have the value SCHED_OTHER, SCHED_FIFO,
       or SCHED_RR. The scheduling parameters for the SCHED_OTHER policy
       are implementation-defined. The SCHED_FIFO and SCHED_RR policies
       shall have a single scheduling parameter, priority.

       If _POSIX_THREAD_SPORADIC_SERVER is defined, then the policy
       argument may have the value SCHED_SPORADIC, with the exception
       for the pthread_setschedparam() function that if the scheduling
       policy was not SCHED_SPORADIC at the time of the call, it is
       implementation-defined whether the function is supported; in
       other words, the implementation need not allow the application to
       dynamically change the scheduling policy to SCHED_SPORADIC. The
       sporadic server scheduling policy has the associated parameters
       sched_ss_low_priority, sched_ss_repl_period,
       sched_ss_init_budget, sched_priority, and sched_ss_max_repl.  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.

       If the pthread_setschedparam() function fails, the scheduling
       parameters shall not be changed for the target thread.

RETURN VALUE         top

       If successful, the pthread_getschedparam() and
       pthread_setschedparam() functions shall return zero; otherwise,
       an error number shall be returned to indicate the error.

ERRORS         top

       The pthread_setschedparam() function shall fail if:

              An attempt was made to set the policy or scheduling
              parameters to an unsupported value.

              An attempt was made to dynamically change the scheduling
              policy to SCHED_SPORADIC, and the implementation does not
              support this change.

       The pthread_setschedparam() function may fail if:

       EINVAL The value specified by policy or one of the scheduling
              parameters associated with the scheduling policy policy is

       EPERM  The caller does not have appropriate privileges to set
              either the scheduling parameters or the scheduling policy
              of the specified thread.

       EPERM  The implementation does not allow the application to
              modify one of the parameters to the value specified.

       These functions shall not return an error code of [EINTR].

       The following sections are informative.

EXAMPLES         top




RATIONALE         top

       If an implementation detects use of a thread ID after the end of
       its lifetime, it is recommended that the function should fail and
       report an [ESRCH] error.



SEE ALSO         top

       pthread_setschedprio(3p), sched_getparam(3p),

       The Base Definitions volume of POSIX.1‐2017, pthread.h(0p),

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic
       form from IEEE Std 1003.1-2017, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The
       Open Group Base Specifications Issue 7, 2018 Edition, Copyright
       (C) 2018 by the Institute of Electrical and Electronics
       Engineers, Inc and The Open Group.  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 .

       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 .

IEEE/The Open Group               2017         PTHREAD_GETSCHEDPARAM(3P)

Pages that refer to this page: pthread.h(0p)pthread_setschedparam(3p)pthread_setschedprio(3p)