source: trunk/sys/libgomp/sections.c @ 1

Last change on this file since 1 was 1, checked in by alain, 5 years ago

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1/* Copyright (C) 2005, 2007, 2008, 2009 Free Software Foundation, Inc.
2   Contributed by Richard Henderson <rth@redhat.com>.
3
4   This file is part of the GNU OpenMP Library (libgomp).
5
6   Libgomp is free software; you can redistribute it and/or modify it
7   under the terms of the GNU General Public License as published by
8   the Free Software Foundation; either version 3, or (at your option)
9   any later version.
10
11   Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
12   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
13   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
14   more details.
15
16   Under Section 7 of GPL version 3, you are granted additional
17   permissions described in the GCC Runtime Library Exception, version
18   3.1, as published by the Free Software Foundation.
19
20   You should have received a copy of the GNU General Public License and
21   a copy of the GCC Runtime Library Exception along with this program;
22   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
23   <http://www.gnu.org/licenses/>.  */
24
25/* This file handles the SECTIONS construct.  */
26
27#include <gomp/libgomp.h>
28
29
30/* Initialize the given work share construct from the given arguments.  */
31
32static inline void
33gomp_sections_init (struct gomp_work_share *ws, unsigned count)
34{
35  ws->sched = GFS_DYNAMIC;
36  ws->chunk_size = 1;
37  ws->end = count + 1;
38  ws->incr = 1;
39  ws->next = 1;
40}
41
42/* This routine is called when first encountering a sections construct
43   that is not bound directly to a parallel construct.  The first thread
44   that arrives will create the work-share construct; subsequent threads
45   will see the construct exists and allocate work from it.
46
47   COUNT is the number of sections in this construct.
48
49   Returns the 1-based section number for this thread to perform, or 0 if
50   all work was assigned to other threads prior to this thread's arrival.  */
51
52unsigned
53GOMP_sections_start (unsigned count)
54{
55  struct gomp_thread *thr = gomp_thread ();
56  long s, e, ret;
57
58  if (gomp_work_share_start (false))
59    {
60      gomp_sections_init (thr->ts.work_share, count);
61      gomp_work_share_init_done ();
62    }
63
64#ifdef HAVE_SYNC_BUILTINS
65  if (gomp_iter_dynamic_next (&s, &e))
66    ret = s;
67  else
68    ret = 0;
69#else
70  gomp_mutex_lock (&thr->ts.work_share->lock);
71  if (gomp_iter_dynamic_next_locked (&s, &e))
72    ret = s;
73  else
74    ret = 0;
75  gomp_mutex_unlock (&thr->ts.work_share->lock);
76#endif
77
78  return ret;
79}
80
81/* This routine is called when the thread completes processing of the
82   section currently assigned to it.  If the work-share construct is
83   bound directly to a parallel construct, then the construct may have
84   been set up before the parallel.  In which case, this may be the
85   first iteration for the thread.
86
87   Returns the 1-based section number for this thread to perform, or 0 if
88   all work was assigned to other threads prior to this thread's arrival.  */
89
90unsigned
91GOMP_sections_next (void)
92{
93  long s, e, ret;
94
95#ifdef HAVE_SYNC_BUILTINS
96  if (gomp_iter_dynamic_next (&s, &e))
97    ret = s;
98  else
99    ret = 0;
100#else
101  struct gomp_thread *thr = gomp_thread ();
102
103  gomp_mutex_lock (&thr->ts.work_share->lock);
104  if (gomp_iter_dynamic_next_locked (&s, &e))
105    ret = s;
106  else
107    ret = 0;
108  gomp_mutex_unlock (&thr->ts.work_share->lock);
109#endif
110
111  return ret;
112}
113
114/* This routine pre-initializes a work-share construct to avoid one
115   synchronization once we get into the loop.  */
116
117void
118GOMP_parallel_sections_start (void (*fn) (void *), void *data,
119                              unsigned num_threads, unsigned count)
120{
121  struct gomp_team *team;
122
123  num_threads = gomp_resolve_num_threads (num_threads, count);
124  team = gomp_new_team (num_threads);
125  gomp_sections_init (&team->work_shares[0], count);
126  gomp_team_start (fn, data, num_threads, team);
127}
128
129/* The GOMP_section_end* routines are called after the thread is told
130   that all sections are complete.  This first version synchronizes
131   all threads; the nowait version does not.  */
132
133void
134GOMP_sections_end (void)
135{
136  gomp_work_share_end ();
137}
138
139void
140GOMP_sections_end_nowait (void)
141{
142  gomp_work_share_end_nowait ();
143}
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