1/*
2 * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the author nor the names of any co-contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * $FreeBSD: releng/10.2/lib/libkse/thread/thr_yield.c 174689 2007-12-16 23:29:57Z deischen $
30 */
31#include <pthread.h>
32#include "thr_private.h"
33
34int _sched_yield(void);
35
36__weak_reference(_sched_yield, sched_yield);
37__weak_reference(_pthread_yield, pthread_yield);
38
39int
40_sched_yield(void)
41{
42	struct pthread	*curthread = _get_curthread();
43
44	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
45		return (__sys_sched_yield());
46
47	/* Reset the accumulated time slice value for the current thread: */
48	curthread->slice_usec = -1;
49
50	/* Schedule the next thread: */
51	_thr_sched_switch(curthread);
52	/* Always return no error. */
53	return(0);
54}
55
56/* Draft 4 yield */
57void
58_pthread_yield(void)
59{
60	struct pthread	*curthread = _get_curthread();
61
62	if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) {
63		__sys_sched_yield();
64		return;
65	}
66
67	/* Reset the accumulated time slice value for the current thread: */
68	curthread->slice_usec = -1;
69
70	/* Schedule the next thread: */
71	_thr_sched_switch(curthread);
72}
73