Manpages - sched_yield.2

sched_yield - yield the processor

  #include <sched.h>

  int sched_yield(void);

*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.

On success, *sched_yield*() returns 0. On error, -1 is returned, and errno is set to indicate the error.

In the Linux implementation, *sched_yield*() always succeeds.

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

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_PRIORITY_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 real-time scheduling policies (i.e., *SCHED_FIFO or SCHED_RR). Use of sched_yield*() with nondeterministic scheduling policies such as *SCHED_OTHER is unspecified and very likely means your application design is broken.

*sched*(7)

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