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 <pthread.h> 46 #ifdef illumos 47 #include <synch.h> 48 #endif 49 #include <stdio.h> 50 51 #include "barrier.h" 52 53 void 54 barrier_init(barrier_t *bar, int nthreads) 55 { 56 pthread_mutex_init(&bar->bar_lock, NULL); 57 #ifdef illumos 58 sema_init(&bar->bar_sem, 0, USYNC_THREAD, NULL); 59 #else 60 sem_init(&bar->bar_sem, 0, 0); 61 #endif 62 63 bar->bar_numin = 0; 64 bar->bar_nthr = nthreads; 65 } 66 67 int 68 barrier_wait(barrier_t *bar) 69 { 70 pthread_mutex_lock(&bar->bar_lock); 71 72 if (++bar->bar_numin < bar->bar_nthr) { 73 pthread_mutex_unlock(&bar->bar_lock); 74 #ifdef illumos 75 sema_wait(&bar->bar_sem); 76 #else 77 sem_wait(&bar->bar_sem); 78 #endif 79 80 return (0); 81 82 } else { 83 int i; 84 85 /* reset for next use */ 86 bar->bar_numin = 0; 87 for (i = 1; i < bar->bar_nthr; i++) 88 #ifdef illumos 89 sema_post(&bar->bar_sem); 90 #else 91 sem_post(&bar->bar_sem); 92 #endif 93 pthread_mutex_unlock(&bar->bar_lock); 94 95 return (1); 96 } 97 } 98