1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License"). You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22
23 #ifdef HAVE_NBTOOL_CONFIG_H
24 #include "nbtool_config.h"
25 #endif
26
27 /*
28 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
29 * Use is subject to license terms.
30 */
31
32 #pragma ident "%Z%%M% %I% %E% SMI"
33
34 /*
35 * This file implements a barrier, a synchronization primitive designed to allow
36 * threads to wait for each other at given points. Barriers are initialized
37 * with a given number of threads, n, using barrier_init(). When a thread calls
38 * barrier_wait(), that thread blocks until n - 1 other threads reach the
39 * barrier_wait() call using the same barrier_t. When n threads have reached
40 * the barrier, they are all awakened and sent on their way. One of the threads
41 * returns from barrier_wait() with a return code of 1; the remaining threads
42 * get a return code of 0.
43 */
44
45 #include <errno.h>
46 #include <pthread.h>
47 #ifdef illumos
48 #include <synch.h>
49 #endif
50 #include <stdio.h>
51
52 #include "barrier.h"
53 #include "ctftools.h"
54
55 void
barrier_init(barrier_t * bar,int nthreads)56 barrier_init(barrier_t *bar, int nthreads)
57 {
58 if ((errno = pthread_mutex_init(&bar->bar_lock, NULL)) != 0)
59 terminate("%s: pthread_mutex_init(bar_lock)", __func__);
60 #ifdef illumos
61 if ((errno = sema_init(&bar->bar_sem, 0, USYNC_THREAD, NULL)) != 0)
62 terminate("%s: sema_init(bar_sem)", __func__);
63 #elif defined(HAVE_DISPATCH_SEMAPHORE_CREATE)
64 if ((bar->bar_sem = dispatch_semaphore_create(0)) == NULL)
65 terminate("%s: dispatch_semaphore_create()\n", __func__);
66 #else
67 if (sem_init(&bar->bar_sem, 0, 0) == -1)
68 terminate("%s: sem_init(bar_sem)", __func__);
69 #endif
70
71 bar->bar_numin = 0;
72 bar->bar_nthr = nthreads;
73 }
74
75 int
barrier_wait(barrier_t * bar)76 barrier_wait(barrier_t *bar)
77 {
78 #if defined(HAVE_DISPATCH_SEMAPHORE_CREATE)
79 long error;
80 #endif
81 if ((errno = pthread_mutex_lock(&bar->bar_lock)) != 0)
82 terminate("%s: pthread_mutex_lock(bar_lock)", __func__);
83
84 if (++bar->bar_numin < bar->bar_nthr) {
85 if ((errno = pthread_mutex_unlock(&bar->bar_lock)) != 0)
86 terminate("%s: pthread_mutex_unlock(bar_lock)",
87 __func__);
88 #ifdef illumos
89 if ((errno = sema_wait(&bar->bar_sem)) != 0)
90 terminate("%s: sema_wait(bar_sem)", __func__);
91 #elif defined(HAVE_DISPATCH_SEMAPHORE_CREATE)
92 if ((error = dispatch_semaphore_wait(bar->bar_sem, DISPATCH_TIME_FOREVER)) != 0)
93 terminate("%s: dispatch_semaphore_wait(bar_sem) = %ld\n",
94 __func__, error);
95 #else
96 if (sem_wait(&bar->bar_sem) == -1)
97 terminate("%s: sem_wait(bar_sem)", __func__);
98 #endif
99
100 return (0);
101
102 } else {
103 int i;
104
105 /* reset for next use */
106 bar->bar_numin = 0;
107 for (i = 1; i < bar->bar_nthr; i++) {
108 #ifdef illumos
109 if ((errno = sema_post(&bar->bar_sem)) != 0)
110 terminate("%s: sema_post(bar_sem)", __func__);
111 #elif defined(HAVE_DISPATCH_SEMAPHORE_CREATE)
112 /* return value doesn't matter */
113 dispatch_semaphore_signal(bar->bar_sem);
114 #else
115 if (sem_post(&bar->bar_sem) == -1)
116 terminate("%s: sem_post(bar_sem)", __func__);
117 #endif
118 }
119 if ((errno = pthread_mutex_unlock(&bar->bar_lock)) != 0)
120 terminate("%s: pthread_mutex_unlock(bar_lock)",
121 __func__);
122
123 return (1);
124 }
125 }
126