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- /* Copyright (C) 2005-2022 Free Software Foundation, Inc.
- Contributed by Richard Henderson <rth@redhat.com>.
- This file is part of the GNU Offloading and Multi Processing Library
- (libgomp).
- Libgomp 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, 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 General Public License for
- more details.
- Under Section 7 of GPL version 3, you are granted additional
- permissions described in the GCC Runtime Library Exception, version
- 3.1, as published by the Free Software Foundation.
- You should have received a copy of the GNU General Public License and
- a copy of the GCC Runtime Library Exception along with this program;
- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
- <http://www.gnu.org/licenses/>. */
- /* 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;
- bar->generation = 0;
- bar->cancellable = false;
- }
- 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, gomp_barrier_state_t state)
- {
- unsigned int n;
- if (state & BAR_WAS_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));
- }
- void
- gomp_team_barrier_wait_end (gomp_barrier_t *bar, gomp_barrier_state_t state)
- {
- unsigned int n;
- state &= ~BAR_CANCELLED;
- if (state & BAR_WAS_LAST)
- {
- n = --bar->arrived;
- struct gomp_thread *thr = gomp_thread ();
- struct gomp_team *team = thr->ts.team;
- team->work_share_cancelled = 0;
- if (team->task_count)
- {
- gomp_barrier_handle_tasks (state);
- if (n > 0)
- gomp_sem_wait (&bar->sem2);
- gomp_mutex_unlock (&bar->mutex1);
- return;
- }
- bar->generation = state + BAR_INCR - BAR_WAS_LAST;
- 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);
- int gen;
- do
- {
- gomp_sem_wait (&bar->sem1);
- gen = __atomic_load_n (&bar->generation, MEMMODEL_ACQUIRE);
- if (gen & BAR_TASK_PENDING)
- {
- gomp_barrier_handle_tasks (state);
- gen = __atomic_load_n (&bar->generation, MEMMODEL_ACQUIRE);
- }
- }
- while (gen != state + BAR_INCR);
- #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);
- }
- }
- bool
- gomp_team_barrier_wait_cancel_end (gomp_barrier_t *bar,
- gomp_barrier_state_t state)
- {
- unsigned int n;
- if (state & BAR_WAS_LAST)
- {
- bar->cancellable = false;
- n = --bar->arrived;
- struct gomp_thread *thr = gomp_thread ();
- struct gomp_team *team = thr->ts.team;
- team->work_share_cancelled = 0;
- if (team->task_count)
- {
- gomp_barrier_handle_tasks (state);
- if (n > 0)
- gomp_sem_wait (&bar->sem2);
- gomp_mutex_unlock (&bar->mutex1);
- return false;
- }
- bar->generation = state + BAR_INCR - BAR_WAS_LAST;
- if (n > 0)
- {
- do
- gomp_sem_post (&bar->sem1);
- while (--n != 0);
- gomp_sem_wait (&bar->sem2);
- }
- gomp_mutex_unlock (&bar->mutex1);
- }
- else
- {
- if (state & BAR_CANCELLED)
- {
- gomp_mutex_unlock (&bar->mutex1);
- return true;
- }
- bar->cancellable = true;
- gomp_mutex_unlock (&bar->mutex1);
- int gen;
- do
- {
- gomp_sem_wait (&bar->sem1);
- gen = __atomic_load_n (&bar->generation, MEMMODEL_ACQUIRE);
- if (gen & BAR_CANCELLED)
- break;
- if (gen & BAR_TASK_PENDING)
- {
- gomp_barrier_handle_tasks (state);
- gen = __atomic_load_n (&bar->generation, MEMMODEL_ACQUIRE);
- if (gen & BAR_CANCELLED)
- break;
- }
- }
- while (gen != state + BAR_INCR);
- #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);
- if (gen & BAR_CANCELLED)
- return true;
- }
- return false;
- }
- void
- gomp_team_barrier_wait (gomp_barrier_t *barrier)
- {
- gomp_team_barrier_wait_end (barrier, gomp_barrier_wait_start (barrier));
- }
- void
- gomp_team_barrier_wake (gomp_barrier_t *bar, int count)
- {
- if (count == 0)
- count = bar->total - 1;
- while (count-- > 0)
- gomp_sem_post (&bar->sem1);
- }
- bool
- gomp_team_barrier_wait_cancel (gomp_barrier_t *bar)
- {
- gomp_barrier_state_t state = gomp_barrier_wait_cancel_start (bar);
- return gomp_team_barrier_wait_cancel_end (bar, state);
- }
- void
- gomp_team_barrier_cancel (struct gomp_team *team)
- {
- if (team->barrier.generation & BAR_CANCELLED)
- return;
- gomp_mutex_lock (&team->barrier.mutex1);
- gomp_mutex_lock (&team->task_lock);
- if (team->barrier.generation & BAR_CANCELLED)
- {
- gomp_mutex_unlock (&team->task_lock);
- gomp_mutex_unlock (&team->barrier.mutex1);
- return;
- }
- team->barrier.generation |= BAR_CANCELLED;
- gomp_mutex_unlock (&team->task_lock);
- if (team->barrier.cancellable)
- {
- int n = team->barrier.arrived;
- if (n > 0)
- {
- do
- gomp_sem_post (&team->barrier.sem1);
- while (--n != 0);
- gomp_sem_wait (&team->barrier.sem2);
- }
- team->barrier.cancellable = false;
- }
- gomp_mutex_unlock (&team->barrier.mutex1);
- }
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