--- /dev/null
+/* Copyright (C) 2005, 2006, 2007, 2008, 2009 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 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 file handles the maintainence of threads in response to team
+ creation and termination. */
+
+#include "libgomp.h"
+#include <stdlib.h>
+#include <string.h>
+
+/* This attribute contains PTHREAD_CREATE_DETACHED. */
+pthread_attr_t gomp_thread_attr;
+
+/* This key is for the thread destructor. */
+pthread_key_t gomp_thread_destructor;
+
+
+/* This is the libgomp per-thread data structure. */
+#ifdef HAVE_TLS
+__thread struct gomp_thread gomp_tls_data;
+#else
+pthread_key_t gomp_tls_key;
+#endif
+
+
+/* This structure is used to communicate across pthread_create. */
+
+struct gomp_thread_start_data
+{
+ void (*fn) (void *);
+ void *fn_data;
+ struct gomp_team_state ts;
+ struct gomp_task *task;
+ struct gomp_thread_pool *thread_pool;
+ bool nested;
+};
+
+
+/* This function is a pthread_create entry point. This contains the idle
+ loop in which a thread waits to be called up to become part of a team. */
+
+static void *
+gomp_thread_start (void *xdata)
+{
+ struct gomp_thread_start_data *data = xdata;
+ struct gomp_thread *thr;
+ struct gomp_thread_pool *pool;
+ void (*local_fn) (void *);
+ void *local_data;
+
+#ifdef HAVE_TLS
+ thr = &gomp_tls_data;
+#else
+ struct gomp_thread local_thr;
+ thr = &local_thr;
+ pthread_setspecific (gomp_tls_key, thr);
+#endif
+ gomp_sem_init (&thr->release, 0);
+
+ /* Extract what we need from data. */
+ local_fn = data->fn;
+ local_data = data->fn_data;
+ thr->thread_pool = data->thread_pool;
+ thr->ts = data->ts;
+ thr->task = data->task;
+
+ thr->ts.team->ordered_release[thr->ts.team_id] = &thr->release;
+
+ /* Make thread pool local. */
+ pool = thr->thread_pool;
+
+ if (data->nested)
+ {
+ struct gomp_team *team = thr->ts.team;
+ struct gomp_task *task = thr->task;
+
+ gomp_barrier_wait (&team->barrier);
+
+ local_fn (local_data);
+ gomp_team_barrier_wait (&team->barrier);
+ gomp_finish_task (task);
+ gomp_barrier_wait_last (&team->barrier);
+ }
+ else
+ {
+ pool->threads[thr->ts.team_id] = thr;
+
+ gomp_barrier_wait (&pool->threads_dock);
+ do
+ {
+ struct gomp_team *team = thr->ts.team;
+ struct gomp_task *task = thr->task;
+
+ local_fn (local_data);
+ gomp_team_barrier_wait (&team->barrier);
+ gomp_finish_task (task);
+
+ gomp_barrier_wait (&pool->threads_dock);
+
+ local_fn = thr->fn;
+ local_data = thr->data;
+ thr->fn = NULL;
+ }
+ while (local_fn);
+ }
+
+ gomp_sem_destroy (&thr->release);
+ return NULL;
+}
+
+
+/* Create a new team data structure. */
+
+struct gomp_team *
+gomp_new_team (unsigned nthreads)
+{
+ struct gomp_team *team;
+ size_t size;
+ int i;
+
+ size = sizeof (*team) + nthreads * (sizeof (team->ordered_release[0])
+ + sizeof (team->implicit_task[0]));
+ team = gomp_malloc (size);
+
+ team->work_share_chunk = 8;
+#ifdef HAVE_SYNC_BUILTINS
+ team->single_count = 0;
+#else
+ gomp_mutex_init (&team->work_share_list_free_lock);
+#endif
+ gomp_init_work_share (&team->work_shares[0], false, nthreads);
+ team->work_shares[0].next_alloc = NULL;
+ team->work_share_list_free = NULL;
+ team->work_share_list_alloc = &team->work_shares[1];
+ for (i = 1; i < 7; i++)
+ team->work_shares[i].next_free = &team->work_shares[i + 1];
+ team->work_shares[i].next_free = NULL;
+
+ team->nthreads = nthreads;
+ gomp_barrier_init (&team->barrier, nthreads);
+
+ gomp_sem_init (&team->master_release, 0);
+ team->ordered_release = (void *) &team->implicit_task[nthreads];
+ team->ordered_release[0] = &team->master_release;
+
+ gomp_mutex_init (&team->task_lock);
+ team->task_queue = NULL;
+ team->task_count = 0;
+ team->task_running_count = 0;
+
+ return team;
+}
+
+
+/* Free a team data structure. */
+
+static void
+free_team (struct gomp_team *team)
+{
+ gomp_barrier_destroy (&team->barrier);
+ gomp_mutex_destroy (&team->task_lock);
+ free (team);
+}
+
+/* Allocate and initialize a thread pool. */
+
+static struct gomp_thread_pool *gomp_new_thread_pool (void)
+{
+ struct gomp_thread_pool *pool
+ = gomp_malloc (sizeof(struct gomp_thread_pool));
+ pool->threads = NULL;
+ pool->threads_size = 0;
+ pool->threads_used = 0;
+ pool->last_team = NULL;
+ return pool;
+}
+
+static void
+gomp_free_pool_helper (void *thread_pool)
+{
+ struct gomp_thread_pool *pool
+ = (struct gomp_thread_pool *) thread_pool;
+ gomp_barrier_wait_last (&pool->threads_dock);
+ gomp_sem_destroy (&gomp_thread ()->release);
+ pthread_exit (NULL);
+}
+
+/* Free a thread pool and release its threads. */
+
+static void
+gomp_free_thread (void *arg __attribute__((unused)))
+{
+ struct gomp_thread *thr = gomp_thread ();
+ struct gomp_thread_pool *pool = thr->thread_pool;
+ if (pool)
+ {
+ if (pool->threads_used > 0)
+ {
+ int i;
+ for (i = 1; i < pool->threads_used; i++)
+ {
+ struct gomp_thread *nthr = pool->threads[i];
+ nthr->fn = gomp_free_pool_helper;
+ nthr->data = pool;
+ }
+ /* This barrier undocks threads docked on pool->threads_dock. */
+ gomp_barrier_wait (&pool->threads_dock);
+ /* And this waits till all threads have called gomp_barrier_wait_last
+ in gomp_free_pool_helper. */
+ gomp_barrier_wait (&pool->threads_dock);
+ /* Now it is safe to destroy the barrier and free the pool. */
+ gomp_barrier_destroy (&pool->threads_dock);
+ }
+ free (pool->threads);
+ if (pool->last_team)
+ free_team (pool->last_team);
+ free (pool);
+ thr->thread_pool = NULL;
+ }
+ if (thr->task != NULL)
+ {
+ struct gomp_task *task = thr->task;
+ gomp_end_task ();
+ free (task);
+ }
+}
+
+/* Launch a team. */
+
+void
+gomp_team_start (void (*fn) (void *), void *data, unsigned nthreads,
+ struct gomp_team *team)
+{
+ struct gomp_thread_start_data *start_data;
+ struct gomp_thread *thr, *nthr;
+ struct gomp_task *task;
+ struct gomp_task_icv *icv;
+ bool nested;
+ struct gomp_thread_pool *pool;
+ unsigned i, n, old_threads_used = 0;
+ pthread_attr_t thread_attr, *attr;
+
+ thr = gomp_thread ();
+ nested = thr->ts.team != NULL;
+ if (__builtin_expect (thr->thread_pool == NULL, 0))
+ {
+ thr->thread_pool = gomp_new_thread_pool ();
+ pthread_setspecific (gomp_thread_destructor, thr);
+ }
+ pool = thr->thread_pool;
+ task = thr->task;
+ icv = task ? &task->icv : &gomp_global_icv;
+
+ /* Always save the previous state, even if this isn't a nested team.
+ In particular, we should save any work share state from an outer
+ orphaned work share construct. */
+ team->prev_ts = thr->ts;
+
+ thr->ts.team = team;
+ thr->ts.team_id = 0;
+ ++thr->ts.level;
+ if (nthreads > 1)
+ ++thr->ts.active_level;
+ thr->ts.work_share = &team->work_shares[0];
+ thr->ts.last_work_share = NULL;
+#ifdef HAVE_SYNC_BUILTINS
+ thr->ts.single_count = 0;
+#endif
+ thr->ts.static_trip = 0;
+ thr->task = &team->implicit_task[0];
+ gomp_init_task (thr->task, task, icv);
+
+ if (nthreads == 1)
+ return;
+
+ i = 1;
+
+ /* We only allow the reuse of idle threads for non-nested PARALLEL
+ regions. This appears to be implied by the semantics of
+ threadprivate variables, but perhaps that's reading too much into
+ things. Certainly it does prevent any locking problems, since
+ only the initial program thread will modify gomp_threads. */
+ if (!nested)
+ {
+ old_threads_used = pool->threads_used;
+
+ if (nthreads <= old_threads_used)
+ n = nthreads;
+ else if (old_threads_used == 0)
+ {
+ n = 0;
+ gomp_barrier_init (&pool->threads_dock, nthreads);
+ }
+ else
+ {
+ n = old_threads_used;
+
+ /* Increase the barrier threshold to make sure all new
+ threads arrive before the team is released. */
+ gomp_barrier_reinit (&pool->threads_dock, nthreads);
+ }
+
+ /* Not true yet, but soon will be. We're going to release all
+ threads from the dock, and those that aren't part of the
+ team will exit. */
+ pool->threads_used = nthreads;
+
+ /* Release existing idle threads. */
+ for (; i < n; ++i)
+ {
+ nthr = pool->threads[i];
+ nthr->ts.team = team;
+ nthr->ts.work_share = &team->work_shares[0];
+ nthr->ts.last_work_share = NULL;
+ nthr->ts.team_id = i;
+ nthr->ts.level = team->prev_ts.level + 1;
+ nthr->ts.active_level = thr->ts.active_level;
+#ifdef HAVE_SYNC_BUILTINS
+ nthr->ts.single_count = 0;
+#endif
+ nthr->ts.static_trip = 0;
+ nthr->task = &team->implicit_task[i];
+ gomp_init_task (nthr->task, task, icv);
+ nthr->fn = fn;
+ nthr->data = data;
+ team->ordered_release[i] = &nthr->release;
+ }
+
+ if (i == nthreads)
+ goto do_release;
+
+ /* If necessary, expand the size of the gomp_threads array. It is
+ expected that changes in the number of threads are rare, thus we
+ make no effort to expand gomp_threads_size geometrically. */
+ if (nthreads >= pool->threads_size)
+ {
+ pool->threads_size = nthreads + 1;
+ pool->threads
+ = gomp_realloc (pool->threads,
+ pool->threads_size
+ * sizeof (struct gomp_thread_data *));
+ }
+ }
+
+ if (__builtin_expect (nthreads > old_threads_used, 0))
+ {
+ long diff = (long) nthreads - (long) old_threads_used;
+
+ if (old_threads_used == 0)
+ --diff;
+
+#ifdef HAVE_SYNC_BUILTINS
+ __sync_fetch_and_add (&gomp_managed_threads, diff);
+#else
+ gomp_mutex_lock (&gomp_remaining_threads_lock);
+ gomp_managed_threads += diff;
+ gomp_mutex_unlock (&gomp_remaining_threads_lock);
+#endif
+ }
+
+ attr = &gomp_thread_attr;
+ if (__builtin_expect (gomp_cpu_affinity != NULL, 0))
+ {
+ size_t stacksize;
+ pthread_attr_init (&thread_attr);
+ pthread_attr_setdetachstate (&thread_attr, PTHREAD_CREATE_DETACHED);
+ if (! pthread_attr_getstacksize (&gomp_thread_attr, &stacksize))
+ pthread_attr_setstacksize (&thread_attr, stacksize);
+ attr = &thread_attr;
+ }
+
+ start_data = gomp_alloca (sizeof (struct gomp_thread_start_data)
+ * (nthreads-i));
+
+ /* Launch new threads. */
+ for (; i < nthreads; ++i, ++start_data)
+ {
+ pthread_t pt;
+ int err;
+
+ start_data->fn = fn;
+ start_data->fn_data = data;
+ start_data->ts.team = team;
+ start_data->ts.work_share = &team->work_shares[0];
+ start_data->ts.last_work_share = NULL;
+ start_data->ts.team_id = i;
+ start_data->ts.level = team->prev_ts.level + 1;
+ start_data->ts.active_level = thr->ts.active_level;
+#ifdef HAVE_SYNC_BUILTINS
+ start_data->ts.single_count = 0;
+#endif
+ start_data->ts.static_trip = 0;
+ start_data->task = &team->implicit_task[i];
+ gomp_init_task (start_data->task, task, icv);
+ start_data->thread_pool = pool;
+ start_data->nested = nested;
+
+ if (gomp_cpu_affinity != NULL)
+ gomp_init_thread_affinity (attr);
+
+ err = pthread_create (&pt, attr, gomp_thread_start, start_data);
+ if (err != 0)
+ gomp_fatal ("Thread creation failed: %s", strerror (err));
+ }
+
+ if (__builtin_expect (gomp_cpu_affinity != NULL, 0))
+ pthread_attr_destroy (&thread_attr);
+
+ do_release:
+ gomp_barrier_wait (nested ? &team->barrier : &pool->threads_dock);
+
+ /* Decrease the barrier threshold to match the number of threads
+ that should arrive back at the end of this team. The extra
+ threads should be exiting. Note that we arrange for this test
+ to never be true for nested teams. */
+ if (__builtin_expect (nthreads < old_threads_used, 0))
+ {
+ long diff = (long) nthreads - (long) old_threads_used;
+
+ gomp_barrier_reinit (&pool->threads_dock, nthreads);
+
+#ifdef HAVE_SYNC_BUILTINS
+ __sync_fetch_and_add (&gomp_managed_threads, diff);
+#else
+ gomp_mutex_lock (&gomp_remaining_threads_lock);
+ gomp_managed_threads += diff;
+ gomp_mutex_unlock (&gomp_remaining_threads_lock);
+#endif
+ }
+}
+
+
+/* Terminate the current team. This is only to be called by the master
+ thread. We assume that we must wait for the other threads. */
+
+void
+gomp_team_end (void)
+{
+ struct gomp_thread *thr = gomp_thread ();
+ struct gomp_team *team = thr->ts.team;
+
+ /* This barrier handles all pending explicit threads. */
+ gomp_team_barrier_wait (&team->barrier);
+ gomp_fini_work_share (thr->ts.work_share);
+
+ gomp_end_task ();
+ thr->ts = team->prev_ts;
+
+ if (__builtin_expect (thr->ts.team != NULL, 0))
+ {
+#ifdef HAVE_SYNC_BUILTINS
+ __sync_fetch_and_add (&gomp_managed_threads, 1L - team->nthreads);
+#else
+ gomp_mutex_lock (&gomp_remaining_threads_lock);
+ gomp_managed_threads -= team->nthreads - 1L;
+ gomp_mutex_unlock (&gomp_remaining_threads_lock);
+#endif
+ /* This barrier has gomp_barrier_wait_last counterparts
+ and ensures the team can be safely destroyed. */
+ gomp_barrier_wait (&team->barrier);
+ }
+
+ if (__builtin_expect (team->work_shares[0].next_alloc != NULL, 0))
+ {
+ struct gomp_work_share *ws = team->work_shares[0].next_alloc;
+ do
+ {
+ struct gomp_work_share *next_ws = ws->next_alloc;
+ free (ws);
+ ws = next_ws;
+ }
+ while (ws != NULL);
+ }
+ gomp_sem_destroy (&team->master_release);
+#ifndef HAVE_SYNC_BUILTINS
+ gomp_mutex_destroy (&team->work_share_list_free_lock);
+#endif
+
+ if (__builtin_expect (thr->ts.team != NULL, 0)
+ || __builtin_expect (team->nthreads == 1, 0))
+ free_team (team);
+ else
+ {
+ struct gomp_thread_pool *pool = thr->thread_pool;
+ if (pool->last_team)
+ free_team (pool->last_team);
+ pool->last_team = team;
+ }
+}
+
+
+/* Constructors for this file. */
+
+static void __attribute__((constructor))
+initialize_team (void)
+{
+ struct gomp_thread *thr;
+
+#ifndef HAVE_TLS
+ static struct gomp_thread initial_thread_tls_data;
+
+ pthread_key_create (&gomp_tls_key, NULL);
+ pthread_setspecific (gomp_tls_key, &initial_thread_tls_data);
+#endif
+
+ if (pthread_key_create (&gomp_thread_destructor, gomp_free_thread) != 0)
+ gomp_fatal ("could not create thread pool destructor.");
+
+#ifdef HAVE_TLS
+ thr = &gomp_tls_data;
+#else
+ thr = &initial_thread_tls_data;
+#endif
+ gomp_sem_init (&thr->release, 0);
+}
+
+static void __attribute__((destructor))
+team_destructor (void)
+{
+ /* Without this dlclose on libgomp could lead to subsequent
+ crashes. */
+ pthread_key_delete (gomp_thread_destructor);
+}
+
+struct gomp_task_icv *
+gomp_new_icv (void)
+{
+ struct gomp_thread *thr = gomp_thread ();
+ struct gomp_task *task = gomp_malloc (sizeof (struct gomp_task));
+ gomp_init_task (task, NULL, &gomp_global_icv);
+ thr->task = task;
+ pthread_setspecific (gomp_thread_destructor, thr);
+ return &task->icv;
+}
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