fg_barrier.c

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/*
 * Copyright (C) 2014 Alexander Zimmermann <alexander.zimmermann@netapp.com>
 * Copyright (C) 2010 Brent Priddy <brent.priddy@priddysoftware.com>
 *
 * This file is part of Flowgrind.
 *
 * Flowgrind is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Flowgrind is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Flowgrind.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /* HAVE_CONFIG_H */
 
#include <pthread.h>
#include <errno.h>
 
#include "fg_definitions.h"
#include "fg_barrier.h"
 
int pthread_barrier_init(pthread_barrier_t *barrier,
                         const pthread_barrierattr_t *attr, unsigned count)
{
        if (unlikely(!barrier) || unlikely(count == 0)) {
                errno = EINVAL;
                return -1;
        }
 
        if (attr && (*attr != PTHREAD_PROCESS_PRIVATE)) {
                errno = EINVAL;
                return -1;
        }
 
        if (pthread_mutex_init(&barrier->mutex, NULL) != 0)
                return -1;
 
        if (pthread_cond_init(&barrier->cond, NULL) != 0) {
                pthread_mutex_destroy(&barrier->mutex);
                return -1;
        }
 
        barrier->tripCount = count;
        barrier->count = 0;
 
        return 0;
}
 
int pthread_barrier_destroy(pthread_barrier_t *barrier)
{
        if (unlikely(!barrier)) {
                errno = EINVAL;
                return -1;
        }
 
        if (pthread_cond_destroy(&barrier->cond) != 0)
                return -1;
 
        if (pthread_mutex_destroy(&barrier->mutex) != 0)
                return -1;
 
        return 0;
}
 
int pthread_barrier_wait(pthread_barrier_t *barrier)
{
        if (unlikely(!barrier)) {
                errno = EINVAL;
                return -1;
        }
 
        if (pthread_mutex_lock(&barrier->mutex) !=0)
                return -1;
        ++(barrier->count);
 
        /* No remaining pthreads, broadcast to wake all waiting threads */
        if (barrier->count >= barrier->tripCount) {
                barrier->count = 0;
                pthread_cond_broadcast(&barrier->cond);
        } else {
                pthread_cond_wait(&barrier->cond, &(barrier->mutex));
        }
 
        pthread_mutex_unlock(&barrier->mutex);
 
        return 0;
}