gcc/libgomp/task.c

365 lines
9.8 KiB
C

/* Copyright (C) 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 tasks in response to task
creation and termination. */
#include "libgomp.h"
#include <stdlib.h>
#include <string.h>
/* Create a new task data structure. */
void
gomp_init_task (struct gomp_task *task, struct gomp_task *parent_task,
struct gomp_task_icv *prev_icv)
{
task->parent = parent_task;
task->icv = *prev_icv;
task->kind = GOMP_TASK_IMPLICIT;
task->in_taskwait = false;
task->in_tied_task = false;
task->children = NULL;
gomp_sem_init (&task->taskwait_sem, 0);
}
/* Clean up a task, after completing it. */
void
gomp_end_task (void)
{
struct gomp_thread *thr = gomp_thread ();
struct gomp_task *task = thr->task;
gomp_finish_task (task);
thr->task = task->parent;
}
static inline void
gomp_clear_parent (struct gomp_task *children)
{
struct gomp_task *task = children;
if (task)
do
{
task->parent = NULL;
task = task->next_child;
}
while (task != children);
}
/* Called when encountering an explicit task directive. If IF_CLAUSE is
false, then we must not delay in executing the task. If UNTIED is true,
then the task may be executed by any member of the team. */
void
GOMP_task (void (*fn) (void *), void *data, void (*cpyfn) (void *, void *),
long arg_size, long arg_align, bool if_clause,
unsigned flags __attribute__((unused)))
{
struct gomp_thread *thr = gomp_thread ();
struct gomp_team *team = thr->ts.team;
#ifdef HAVE_BROKEN_POSIX_SEMAPHORES
/* If pthread_mutex_* is used for omp_*lock*, then each task must be
tied to one thread all the time. This means UNTIED tasks must be
tied and if CPYFN is non-NULL IF(0) must be forced, as CPYFN
might be running on different thread than FN. */
if (cpyfn)
if_clause = false;
if (flags & 1)
flags &= ~1;
#endif
if (!if_clause || team == NULL
|| team->task_count > 64 * team->nthreads)
{
struct gomp_task task;
gomp_init_task (&task, thr->task, gomp_icv (false));
task.kind = GOMP_TASK_IFFALSE;
if (thr->task)
task.in_tied_task = thr->task->in_tied_task;
thr->task = &task;
if (__builtin_expect (cpyfn != NULL, 0))
{
char buf[arg_size + arg_align - 1];
char *arg = (char *) (((uintptr_t) buf + arg_align - 1)
& ~(uintptr_t) (arg_align - 1));
cpyfn (arg, data);
fn (arg);
}
else
fn (data);
if (task.children)
{
gomp_mutex_lock (&team->task_lock);
gomp_clear_parent (task.children);
gomp_mutex_unlock (&team->task_lock);
}
gomp_end_task ();
}
else
{
struct gomp_task *task;
struct gomp_task *parent = thr->task;
char *arg;
bool do_wake;
task = gomp_malloc (sizeof (*task) + arg_size + arg_align - 1);
arg = (char *) (((uintptr_t) (task + 1) + arg_align - 1)
& ~(uintptr_t) (arg_align - 1));
gomp_init_task (task, parent, gomp_icv (false));
task->kind = GOMP_TASK_IFFALSE;
task->in_tied_task = parent->in_tied_task;
thr->task = task;
if (cpyfn)
cpyfn (arg, data);
else
memcpy (arg, data, arg_size);
thr->task = parent;
task->kind = GOMP_TASK_WAITING;
task->fn = fn;
task->fn_data = arg;
task->in_tied_task = true;
gomp_mutex_lock (&team->task_lock);
if (parent->children)
{
task->next_child = parent->children;
task->prev_child = parent->children->prev_child;
task->next_child->prev_child = task;
task->prev_child->next_child = task;
}
else
{
task->next_child = task;
task->prev_child = task;
}
parent->children = task;
if (team->task_queue)
{
task->next_queue = team->task_queue;
task->prev_queue = team->task_queue->prev_queue;
task->next_queue->prev_queue = task;
task->prev_queue->next_queue = task;
}
else
{
task->next_queue = task;
task->prev_queue = task;
team->task_queue = task;
}
++team->task_count;
gomp_team_barrier_set_task_pending (&team->barrier);
do_wake = team->task_running_count + !parent->in_tied_task
< team->nthreads;
gomp_mutex_unlock (&team->task_lock);
if (do_wake)
gomp_team_barrier_wake (&team->barrier, 1);
}
}
void
gomp_barrier_handle_tasks (gomp_barrier_state_t state)
{
struct gomp_thread *thr = gomp_thread ();
struct gomp_team *team = thr->ts.team;
struct gomp_task *task = thr->task;
struct gomp_task *child_task = NULL;
struct gomp_task *to_free = NULL;
gomp_mutex_lock (&team->task_lock);
if (gomp_barrier_last_thread (state))
{
if (team->task_count == 0)
{
gomp_team_barrier_done (&team->barrier, state);
gomp_mutex_unlock (&team->task_lock);
gomp_team_barrier_wake (&team->barrier, 0);
return;
}
gomp_team_barrier_set_waiting_for_tasks (&team->barrier);
}
while (1)
{
if (team->task_queue != NULL)
{
struct gomp_task *parent;
child_task = team->task_queue;
parent = child_task->parent;
if (parent && parent->children == child_task)
parent->children = child_task->next_child;
child_task->prev_queue->next_queue = child_task->next_queue;
child_task->next_queue->prev_queue = child_task->prev_queue;
if (child_task->next_queue != child_task)
team->task_queue = child_task->next_queue;
else
team->task_queue = NULL;
child_task->kind = GOMP_TASK_TIED;
team->task_running_count++;
if (team->task_count == team->task_running_count)
gomp_team_barrier_clear_task_pending (&team->barrier);
}
gomp_mutex_unlock (&team->task_lock);
if (to_free)
{
gomp_finish_task (to_free);
free (to_free);
to_free = NULL;
}
if (child_task)
{
thr->task = child_task;
child_task->fn (child_task->fn_data);
thr->task = task;
}
else
return;
gomp_mutex_lock (&team->task_lock);
if (child_task)
{
struct gomp_task *parent = child_task->parent;
if (parent)
{
child_task->prev_child->next_child = child_task->next_child;
child_task->next_child->prev_child = child_task->prev_child;
if (parent->children == child_task)
{
if (child_task->next_child != child_task)
parent->children = child_task->next_child;
else
{
parent->children = NULL;
if (parent->in_taskwait)
gomp_sem_post (&parent->taskwait_sem);
}
}
}
gomp_clear_parent (child_task->children);
to_free = child_task;
child_task = NULL;
team->task_running_count--;
if (--team->task_count == 0
&& gomp_team_barrier_waiting_for_tasks (&team->barrier))
{
gomp_team_barrier_done (&team->barrier, state);
gomp_mutex_unlock (&team->task_lock);
gomp_team_barrier_wake (&team->barrier, 0);
}
}
}
}
/* Called when encountering a taskwait directive. */
void
GOMP_taskwait (void)
{
struct gomp_thread *thr = gomp_thread ();
struct gomp_team *team = thr->ts.team;
struct gomp_task *task = thr->task;
struct gomp_task *child_task = NULL;
struct gomp_task *to_free = NULL;
if (task == NULL || task->children == NULL)
return;
gomp_mutex_lock (&team->task_lock);
while (1)
{
if (task->children == NULL)
{
gomp_mutex_unlock (&team->task_lock);
if (to_free)
{
gomp_finish_task (to_free);
free (to_free);
}
return;
}
if (task->children->kind == GOMP_TASK_WAITING)
{
child_task = task->children;
task->children = child_task->next_child;
child_task->prev_queue->next_queue = child_task->next_queue;
child_task->next_queue->prev_queue = child_task->prev_queue;
if (team->task_queue == child_task)
{
if (child_task->next_queue != child_task)
team->task_queue = child_task->next_queue;
else
team->task_queue = NULL;
}
child_task->kind = GOMP_TASK_TIED;
team->task_running_count++;
if (team->task_count == team->task_running_count)
gomp_team_barrier_clear_task_pending (&team->barrier);
}
else
/* All tasks we are waiting for are already running
in other threads. Wait for them. */
task->in_taskwait = true;
gomp_mutex_unlock (&team->task_lock);
if (to_free)
{
gomp_finish_task (to_free);
free (to_free);
to_free = NULL;
}
if (child_task)
{
thr->task = child_task;
child_task->fn (child_task->fn_data);
thr->task = task;
}
else
{
gomp_sem_wait (&task->taskwait_sem);
task->in_taskwait = false;
return;
}
gomp_mutex_lock (&team->task_lock);
if (child_task)
{
child_task->prev_child->next_child = child_task->next_child;
child_task->next_child->prev_child = child_task->prev_child;
if (task->children == child_task)
{
if (child_task->next_child != child_task)
task->children = child_task->next_child;
else
task->children = NULL;
}
gomp_clear_parent (child_task->children);
to_free = child_task;
child_task = NULL;
team->task_count--;
team->task_running_count--;
}
}
}