/* Copyright (C) 2005 Free Software Foundation, Inc. Contributed by Richard Henderson <rth@redhat.com>. This file is part of the GNU OpenMP Library (libgomp). Libgomp is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. Libgomp 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with libgomp; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ /* As a special exception, if you link this library with other files, some of which are compiled with GCC, to produce an executable, this library does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License. */ /* This is the default implementation of a barrier synchronization mechanism for libgomp. This type is private to the library. Note that we rely on being able to adjust the barrier count while threads are blocked, so the POSIX pthread_barrier_t won't work. */ #include "libgomp.h" void gomp_barrier_init (gomp_barrier_t *bar, unsigned count) { gomp_mutex_init (&bar->mutex1); #ifndef HAVE_SYNC_BUILTINS gomp_mutex_init (&bar->mutex2); #endif gomp_sem_init (&bar->sem1, 0); gomp_sem_init (&bar->sem2, 0); bar->total = count; bar->arrived = 0; } void gomp_barrier_destroy (gomp_barrier_t *bar) { /* Before destroying, make sure all threads have left the barrier. */ gomp_mutex_lock (&bar->mutex1); gomp_mutex_unlock (&bar->mutex1); gomp_mutex_destroy (&bar->mutex1); #ifndef HAVE_SYNC_BUILTINS gomp_mutex_destroy (&bar->mutex2); #endif gomp_sem_destroy (&bar->sem1); gomp_sem_destroy (&bar->sem2); } void gomp_barrier_reinit (gomp_barrier_t *bar, unsigned count) { gomp_mutex_lock (&bar->mutex1); bar->total = count; gomp_mutex_unlock (&bar->mutex1); } void gomp_barrier_wait_end (gomp_barrier_t *bar, bool last) { unsigned int n; if (last) { n = --bar->arrived; if (n > 0) { do gomp_sem_post (&bar->sem1); while (--n != 0); gomp_sem_wait (&bar->sem2); } gomp_mutex_unlock (&bar->mutex1); } else { gomp_mutex_unlock (&bar->mutex1); gomp_sem_wait (&bar->sem1); #ifdef HAVE_SYNC_BUILTINS n = __sync_add_and_fetch (&bar->arrived, -1); #else gomp_mutex_lock (&bar->mutex2); n = --bar->arrived; gomp_mutex_unlock (&bar->mutex2); #endif if (n == 0) gomp_sem_post (&bar->sem2); } } void gomp_barrier_wait (gomp_barrier_t *barrier) { gomp_barrier_wait_end (barrier, gomp_barrier_wait_start (barrier)); }