sched_get_priority_max(2) — Linux manual page

sched_get_priority_max(2)  System Calls Manual sched_get_priority_max(2)

NAME

       sched_get_priority_max, sched_get_priority_min  - get static
       priority range

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <sched.h>

       int sched_get_priority_max(int policy);
       int sched_get_priority_min(int policy);

DESCRIPTION

       sched_get_priority_max() returns the maximum priority value that
       can be used with the scheduling algorithm identified by policy.
       sched_get_priority_min() returns the minimum priority value that
       can be used with the scheduling algorithm identified by policy.
       Supported policy values are SCHED_FIFO, SCHED_RR, SCHED_OTHER,
       SCHED_BATCH, SCHED_IDLE, and SCHED_DEADLINE.  Further details
       about these policies can be found in sched(7).

       Processes with numerically higher priority values are scheduled
       before processes with numerically lower priority values.  Thus,
       the value returned by sched_get_priority_max() will be greater
       than the value returned by sched_get_priority_min().

       Linux allows the static priority range 1 to 99 for the SCHED_FIFO
       and SCHED_RR policies, and the priority 0 for the remaining
       policies.  Scheduling priority ranges for the various policies
       are not alterable.

       The range of scheduling priorities may vary on other POSIX
       systems, thus it is a good idea for portable applications to use
       a virtual priority range and map it to the interval given by
       sched_get_priority_max() and sched_get_priority_min() POSIX.1
       requires a spread of at least 32 between the maximum and the
       minimum values for SCHED_FIFO and SCHED_RR.

       POSIX systems on which sched_get_priority_max() and
       sched_get_priority_min() are available define
       _POSIX_PRIORITY_SCHEDULING in <unistd.h>.

RETURN VALUE

       On success, sched_get_priority_max() and sched_get_priority_min()
       return the maximum/minimum priority value for the named
       scheduling policy.  On error, -1 is returned, and errno is set to
       indicate the error.

ERRORS

       EINVAL The argument policy does not identify a defined scheduling
              policy.

STANDARDS

       POSIX.1-2008.

HISTORY

       POSIX.1-2001.

SEE ALSO

       sched_getaffinity(2), sched_getparam(2), sched_getscheduler(2),
       sched_setaffinity(2), sched_setparam(2), sched_setscheduler(2),
       sched(7)

COLOPHON

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Linux man-pages 6.9.1          2024-05-02      sched_get_priority_max(2)

Pages that refer to this page: sched_setaffinity(2), sched_setattr(2), sched_setparam(2), sched_setscheduler(2), syscalls(2), pthread_attr_setschedparam(3), pthread_setschedparam(3), pthread_setschedprio(3), sched(7)

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