1 /* Copyright (C) 2005, 2007, 2008, 2009, 2010 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 "libgomp.h" 28 29 30 /* Initialize the given work share construct from the given arguments. */ 31 32 static inline void 33 gomp_sections_init (struct gomp_work_share *ws, unsigned count) 34 { 35 ws->sched = GFS_DYNAMIC; 36 ws->chunk_size = 1; 37 ws->end = count + 1L; 38 ws->incr = 1; 39 ws->next = 1; 40 #ifdef HAVE_SYNC_BUILTINS 41 /* Prepare things to make each iteration faster. */ 42 if (sizeof (long) > sizeof (unsigned)) 43 ws->mode = 1; 44 else 45 { 46 struct gomp_thread *thr = gomp_thread (); 47 struct gomp_team *team = thr->ts.team; 48 long nthreads = team ? team->nthreads : 1; 49 50 ws->mode = ((nthreads | ws->end) 51 < 1UL << (sizeof (long) * __CHAR_BIT__ / 2 - 1)); 52 } 53 #else 54 ws->mode = 0; 55 #endif 56 } 57 58 /* This routine is called when first encountering a sections construct 59 that is not bound directly to a parallel construct. The first thread 60 that arrives will create the work-share construct; subsequent threads 61 will see the construct exists and allocate work from it. 62 63 COUNT is the number of sections in this construct. 64 65 Returns the 1-based section number for this thread to perform, or 0 if 66 all work was assigned to other threads prior to this thread's arrival. */ 67 68 unsigned 69 GOMP_sections_start (unsigned count) 70 { 71 struct gomp_thread *thr = gomp_thread (); 72 long s, e, ret; 73 74 if (gomp_work_share_start (false)) 75 { 76 gomp_sections_init (thr->ts.work_share, count); 77 gomp_work_share_init_done (); 78 } 79 80 #ifdef HAVE_SYNC_BUILTINS 81 if (gomp_iter_dynamic_next (&s, &e)) 82 ret = s; 83 else 84 ret = 0; 85 #else 86 gomp_mutex_lock (&thr->ts.work_share->lock); 87 if (gomp_iter_dynamic_next_locked (&s, &e)) 88 ret = s; 89 else 90 ret = 0; 91 gomp_mutex_unlock (&thr->ts.work_share->lock); 92 #endif 93 94 return ret; 95 } 96 97 /* This routine is called when the thread completes processing of the 98 section currently assigned to it. If the work-share construct is 99 bound directly to a parallel construct, then the construct may have 100 been set up before the parallel. In which case, this may be the 101 first iteration for the thread. 102 103 Returns the 1-based section number for this thread to perform, or 0 if 104 all work was assigned to other threads prior to this thread's arrival. */ 105 106 unsigned 107 GOMP_sections_next (void) 108 { 109 long s, e, ret; 110 111 #ifdef HAVE_SYNC_BUILTINS 112 if (gomp_iter_dynamic_next (&s, &e)) 113 ret = s; 114 else 115 ret = 0; 116 #else 117 struct gomp_thread *thr = gomp_thread (); 118 119 gomp_mutex_lock (&thr->ts.work_share->lock); 120 if (gomp_iter_dynamic_next_locked (&s, &e)) 121 ret = s; 122 else 123 ret = 0; 124 gomp_mutex_unlock (&thr->ts.work_share->lock); 125 #endif 126 127 return ret; 128 } 129 130 /* This routine pre-initializes a work-share construct to avoid one 131 synchronization once we get into the loop. */ 132 133 void 134 GOMP_parallel_sections_start (void (*fn) (void *), void *data, 135 unsigned num_threads, unsigned count) 136 { 137 struct gomp_team *team; 138 139 num_threads = gomp_resolve_num_threads (num_threads, count); 140 team = gomp_new_team (num_threads); 141 gomp_sections_init (&team->work_shares[0], count); 142 gomp_team_start (fn, data, num_threads, team); 143 } 144 145 /* The GOMP_section_end* routines are called after the thread is told 146 that all sections are complete. This first version synchronizes 147 all threads; the nowait version does not. */ 148 149 void 150 GOMP_sections_end (void) 151 { 152 gomp_work_share_end (); 153 } 154 155 void 156 GOMP_sections_end_nowait (void) 157 { 158 gomp_work_share_end_nowait (); 159 } 160