1 /* Copyright (C) 2005-2018 Free Software Foundation, Inc. 2 Contributed by Richard Henderson <rth@redhat.com>. 3 4 This file is part of the GNU Offloading and Multi Processing Library 5 (libgomp). 6 7 Libgomp is free software; you can redistribute it and/or modify it 8 under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3, or (at your option) 10 any later version. 11 12 Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY 13 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 14 FOR A PARTICULAR PURPOSE. See the GNU General Public License for 15 more details. 16 17 Under Section 7 of GPL version 3, you are granted additional 18 permissions described in the GCC Runtime Library Exception, version 19 3.1, as published by the Free Software Foundation. 20 21 You should have received a copy of the GNU General Public License and 22 a copy of the GCC Runtime Library Exception along with this program; 23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 24 <http://www.gnu.org/licenses/>. */ 25 26 /* This file handles the SECTIONS construct. */ 27 28 #include "libgomp.h" 29 30 31 /* Initialize the given work share construct from the given arguments. */ 32 33 static inline void 34 gomp_sections_init (struct gomp_work_share *ws, unsigned count) 35 { 36 ws->sched = GFS_DYNAMIC; 37 ws->chunk_size = 1; 38 ws->end = count + 1L; 39 ws->incr = 1; 40 ws->next = 1; 41 #ifdef HAVE_SYNC_BUILTINS 42 /* Prepare things to make each iteration faster. */ 43 if (sizeof (long) > sizeof (unsigned)) 44 ws->mode = 1; 45 else 46 { 47 struct gomp_thread *thr = gomp_thread (); 48 struct gomp_team *team = thr->ts.team; 49 long nthreads = team ? team->nthreads : 1; 50 51 ws->mode = ((nthreads | ws->end) 52 < 1UL << (sizeof (long) * __CHAR_BIT__ / 2 - 1)); 53 } 54 #else 55 ws->mode = 0; 56 #endif 57 } 58 59 /* This routine is called when first encountering a sections construct 60 that is not bound directly to a parallel construct. The first thread 61 that arrives will create the work-share construct; subsequent threads 62 will see the construct exists and allocate work from it. 63 64 COUNT is the number of sections in this construct. 65 66 Returns the 1-based section number for this thread to perform, or 0 if 67 all work was assigned to other threads prior to this thread's arrival. */ 68 69 unsigned 70 GOMP_sections_start (unsigned count) 71 { 72 struct gomp_thread *thr = gomp_thread (); 73 long s, e, ret; 74 75 if (gomp_work_share_start (false)) 76 { 77 gomp_sections_init (thr->ts.work_share, count); 78 gomp_work_share_init_done (); 79 } 80 81 #ifdef HAVE_SYNC_BUILTINS 82 if (gomp_iter_dynamic_next (&s, &e)) 83 ret = s; 84 else 85 ret = 0; 86 #else 87 gomp_mutex_lock (&thr->ts.work_share->lock); 88 if (gomp_iter_dynamic_next_locked (&s, &e)) 89 ret = s; 90 else 91 ret = 0; 92 gomp_mutex_unlock (&thr->ts.work_share->lock); 93 #endif 94 95 return ret; 96 } 97 98 /* This routine is called when the thread completes processing of the 99 section currently assigned to it. If the work-share construct is 100 bound directly to a parallel construct, then the construct may have 101 been set up before the parallel. In which case, this may be the 102 first iteration for the thread. 103 104 Returns the 1-based section number for this thread to perform, or 0 if 105 all work was assigned to other threads prior to this thread's arrival. */ 106 107 unsigned 108 GOMP_sections_next (void) 109 { 110 long s, e, ret; 111 112 #ifdef HAVE_SYNC_BUILTINS 113 if (gomp_iter_dynamic_next (&s, &e)) 114 ret = s; 115 else 116 ret = 0; 117 #else 118 struct gomp_thread *thr = gomp_thread (); 119 120 gomp_mutex_lock (&thr->ts.work_share->lock); 121 if (gomp_iter_dynamic_next_locked (&s, &e)) 122 ret = s; 123 else 124 ret = 0; 125 gomp_mutex_unlock (&thr->ts.work_share->lock); 126 #endif 127 128 return ret; 129 } 130 131 /* This routine pre-initializes a work-share construct to avoid one 132 synchronization once we get into the loop. */ 133 134 void 135 GOMP_parallel_sections_start (void (*fn) (void *), void *data, 136 unsigned num_threads, unsigned count) 137 { 138 struct gomp_team *team; 139 140 num_threads = gomp_resolve_num_threads (num_threads, count); 141 team = gomp_new_team (num_threads); 142 gomp_sections_init (&team->work_shares[0], count); 143 gomp_team_start (fn, data, num_threads, 0, team); 144 } 145 146 ialias_redirect (GOMP_parallel_end) 147 148 void 149 GOMP_parallel_sections (void (*fn) (void *), void *data, 150 unsigned num_threads, unsigned count, unsigned flags) 151 { 152 struct gomp_team *team; 153 154 num_threads = gomp_resolve_num_threads (num_threads, count); 155 team = gomp_new_team (num_threads); 156 gomp_sections_init (&team->work_shares[0], count); 157 gomp_team_start (fn, data, num_threads, flags, team); 158 fn (data); 159 GOMP_parallel_end (); 160 } 161 162 /* The GOMP_section_end* routines are called after the thread is told 163 that all sections are complete. The first two versions synchronize 164 all threads; the nowait version does not. */ 165 166 void 167 GOMP_sections_end (void) 168 { 169 gomp_work_share_end (); 170 } 171 172 bool 173 GOMP_sections_end_cancel (void) 174 { 175 return gomp_work_share_end_cancel (); 176 } 177 178 void 179 GOMP_sections_end_nowait (void) 180 { 181 gomp_work_share_end_nowait (); 182 } 183