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/* Copyright (C) 2005, 2007, 2008, 2009, 2010 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 SECTIONS construct. */
#include "libgomp.h"
/* Initialize the given work share construct from the given arguments. */
static inline void
gomp_sections_init (struct gomp_work_share *ws, unsigned count)
{
ws->sched = GFS_DYNAMIC;
ws->chunk_size = 1;
ws->end = count + 1L;
ws->incr = 1;
ws->next = 1;
#ifdef HAVE_SYNC_BUILTINS
/* Prepare things to make each iteration faster. */
if (sizeof (long) > sizeof (unsigned))
ws->mode = 1;
else
{
struct gomp_thread *thr = gomp_thread ();
struct gomp_team *team = thr->ts.team;
long nthreads = team ? team->nthreads : 1;
ws->mode = ((nthreads | ws->end)
< 1UL << (sizeof (long) * __CHAR_BIT__ / 2 - 1));
}
#else
ws->mode = 0;
#endif
}
/* This routine is called when first encountering a sections construct
that is not bound directly to a parallel construct. The first thread
that arrives will create the work-share construct; subsequent threads
will see the construct exists and allocate work from it.
COUNT is the number of sections in this construct.
Returns the 1-based section number for this thread to perform, or 0 if
all work was assigned to other threads prior to this thread's arrival. */
unsigned
GOMP_sections_start (unsigned count)
{
struct gomp_thread *thr = gomp_thread ();
long s, e, ret;
if (gomp_work_share_start (false))
{
gomp_sections_init (thr->ts.work_share, count);
gomp_work_share_init_done ();
}
#ifdef HAVE_SYNC_BUILTINS
if (gomp_iter_dynamic_next (&s, &e))
ret = s;
else
ret = 0;
#else
gomp_mutex_lock (&thr->ts.work_share->lock);
if (gomp_iter_dynamic_next_locked (&s, &e))
ret = s;
else
ret = 0;
gomp_mutex_unlock (&thr->ts.work_share->lock);
#endif
return ret;
}
/* This routine is called when the thread completes processing of the
section currently assigned to it. If the work-share construct is
bound directly to a parallel construct, then the construct may have
been set up before the parallel. In which case, this may be the
first iteration for the thread.
Returns the 1-based section number for this thread to perform, or 0 if
all work was assigned to other threads prior to this thread's arrival. */
unsigned
GOMP_sections_next (void)
{
long s, e, ret;
#ifdef HAVE_SYNC_BUILTINS
if (gomp_iter_dynamic_next (&s, &e))
ret = s;
else
ret = 0;
#else
struct gomp_thread *thr = gomp_thread ();
gomp_mutex_lock (&thr->ts.work_share->lock);
if (gomp_iter_dynamic_next_locked (&s, &e))
ret = s;
else
ret = 0;
gomp_mutex_unlock (&thr->ts.work_share->lock);
#endif
return ret;
}
/* This routine pre-initializes a work-share construct to avoid one
synchronization once we get into the loop. */
void
GOMP_parallel_sections_start (void (*fn) (void *), void *data,
unsigned num_threads, unsigned count)
{
struct gomp_team *team;
num_threads = gomp_resolve_num_threads (num_threads, count);
team = gomp_new_team (num_threads);
gomp_sections_init (&team->work_shares[0], count);
gomp_team_start (fn, data, num_threads, team);
}
/* The GOMP_section_end* routines are called after the thread is told
that all sections are complete. This first version synchronizes
all threads; the nowait version does not. */
void
GOMP_sections_end (void)
{
gomp_work_share_end ();
}
void
GOMP_sections_end_nowait (void)
{
gomp_work_share_end_nowait ();
}
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