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SCHED_YIELD(2) Linux Programmer's Manual SCHED_YIELD(2)

NAME

     sched_yield - yield the processor

SYNOPSIS

     #include <sched.h>

     int sched_yield(void);

DESCRIPTION

     sched_yield()  causes  the  calling  thread to relinquish the CPU.  The
     thread is moved to the end of the queue for its static priority  and  a
     new thread gets to run.

RETURN VALUE

     On  success,  sched_yield()  returns  0.  On error, -1 is returned, and
     errno is set appropriately.

ERRORS

     In the Linux implementation, sched_yield() always succeeds.

CONFORMING TO

     POSIX.1-2001, POSIX.1-2008.

NOTES

     If the calling thread is the only thread in the highest  priority  list
     at that time, it will continue to run after a call to sched_yield().

     POSIX  systems on which sched_yield() is available define _POSIX_PRIOR-
     ITY_SCHEDULING in <unistd.h>.

     Strategic calls to sched_yield()  can  improve  performance  by  giving
     other  threads  or  processes  a chance to run when (heavily) contended
     resources (e.g., mutexes) have been  released  by  the  caller.   Avoid
     calling  sched_yield()  unnecessarily  or  inappropriately  (e.g., when
     resources needed by other schedulable threads are  still  held  by  the
     caller),  since  doing  so will result in unnecessary context switches,
     which will degrade system performance.

     sched_yield() is intended for use with  read-time  scheduling  policies
     (i.e., SCHED_FIFO or SCHED_RR).  Use of sched_yield() with nondetermin-
     istic scheduling policies such as SCHED_OTHER is unspecified  and  very
     likely means your application design is broken.

SEE ALSO

     sched(7)

COLOPHON

     This  page  is  part of release 4.16 of the Linux man-pages project.  A
     description of the project, information about reporting bugs,  and  the
     latest     version     of     this    page,    can    be    found    at
     https://www.kernel.org/doc/man-pages/.

Linux 2017-09-15 SCHED_YIELD(2)