sched_setscheduler(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

       sched_setscheduler — set scheduling policy and parameters

SYNOPSIS         top

       #include <sched.h>

       int sched_setscheduler(pid_t pid, int policy,
           const struct sched_param *param);

DESCRIPTION         top

       The sched_setscheduler() function shall set the scheduling policy
       and scheduling parameters of the process specified by pid to
       policy and the parameters specified in the sched_param structure
       pointed to by param, respectively. The value of the
       sched_priority member in the sched_param structure shall be any
       integer within the inclusive priority range for the scheduling
       policy specified by policy.  If the value of pid is negative, the
       behavior of the sched_setscheduler() function is unspecified.

       The possible values for the policy parameter are defined in the
       <sched.h> header.

       If a process specified by pid exists, and if the calling process
       has permission, the scheduling policy and scheduling parameters
       shall be set for the process whose process ID is equal to pid.

       If pid is zero, the scheduling policy and scheduling parameters
       shall be set for the calling process.

       The conditions under which one process has appropriate privileges
       to change the scheduling parameters of another process are

       Implementations may require that the requesting process have
       permission to set its own scheduling parameters or those of
       another process.  Additionally, implementation-defined
       restrictions may apply as to the appropriate privileges required
       to set the scheduling policy of the process, or the scheduling
       policy of another process, to a particular value.

       The sched_setscheduler() function shall be considered successful
       if it succeeds in setting the scheduling policy and scheduling
       parameters of the process specified by pid to the values
       specified by policy and the structure pointed to by param,

       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

       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 and
       associated scheduling parameters for the underlying kernel-
       scheduled entities used by the process contention scope threads.

RETURN VALUE         top

       Upon successful completion, the function shall return the former
       scheduling policy of the specified process. If the
       sched_setscheduler() function fails to complete successfully, the
       policy and scheduling parameters shall remain unchanged, and the
       function shall return a value of -1 and set errno to indicate the

ERRORS         top

       The sched_setscheduler() function shall fail if:

       EINVAL The value of the policy parameter is invalid, or one or
              more of the parameters contained in param is outside the
              valid range for the specified scheduling policy.

       EPERM  The requesting process does not have permission to set
              either or both of the scheduling parameters or the
              scheduling policy of the specified process.

       ESRCH  No process can be found corresponding to that specified by

       The following sections are informative.

EXAMPLES         top




RATIONALE         top




SEE ALSO         top

       Scheduling Policies, sched_getparam(3p), sched_getscheduler(3p),

       The Base Definitions volume of POSIX.1‐2017, sched.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            SCHED_SETSCHEDULER(3P)

Pages that refer to this page: sched.h(0p)getpriority(3p)posix_spawn(3p)sched_getparam(3p)sched_get_priority_max(3p)sched_getscheduler(3p)sched_rr_get_interval(3p)sched_setparam(3p)