Hi Andrew,
Here's a patch set for discouraging sched_yield(2). See the formatted
page at the bottom. I also updated some POSIX historic detail.
Cheers,
Alex
Alejandro Colomar (3):
sched_yield.2: HISTORY: POSIX.1-2008 makes this non-optional
sched_yield.2: NOTES: Remove misleading sentence
sched_yield.2: Rename NOTES to CAVEATS, and reorder contents
man2/sched_yield.2 | 41 +++++++++++++++++++----------------------
1 file changed, 19 insertions(+), 22 deletions(-)
---
$ MANWIDTH=72 man ./man2/sched_yield.2 | cat
sched_yield(2) System Calls Manual sched_yield(2)
NAME
sched_yield - yield the processor
LIBRARY
Standard C library (libc, -lc)
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 pri‐
ority and a new thread gets to run.
RETURN VALUE
On success, sched_yield() returns 0. On error, -1 is returned,
and errno is set to indicate the error.
ERRORS
In the Linux implementation, sched_yield() always succeeds.
STANDARDS
POSIX.1‐2008.
HISTORY
POSIX.1‐2001 (but optional). POSIX.1‐2008.
Before POSIX.1‐2008, systems on which sched_yield() is avail‐
able defined _POSIX_PRIORITY_SCHEDULING in <unistd.h>.
CAVEATS
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.
If the calling thread is the only thread in the highest prior‐
ity list at that time, it will continue to run after a call to
sched_yield().
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 unnec‐
essary context switches, which will degrade system performance.
SEE ALSO
sched(7)
Linux man‐pages (unreleased) (date) sched_yield(2)
--
2.40.1
