| /* 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)); |
| } |