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 is the default implementation of a barrier synchronization mechanism 27 for libgomp. This type is private to the library. Note that we rely on 28 being able to adjust the barrier count while threads are blocked, so the 29 POSIX pthread_barrier_t won't work. */ 30 31 #ifndef GOMP_BARRIER_H 32 #define GOMP_BARRIER_H 1 33 34 #include <pthread.h> 35 36 typedef struct 37 { 38 gomp_mutex_t mutex1; 39 #ifndef HAVE_SYNC_BUILTINS 40 gomp_mutex_t mutex2; 41 #endif 42 gomp_sem_t sem1; 43 gomp_sem_t sem2; 44 unsigned total; 45 unsigned arrived; 46 unsigned generation; 47 bool cancellable; 48 } gomp_barrier_t; 49 50 typedef unsigned int gomp_barrier_state_t; 51 52 /* The generation field contains a counter in the high bits, with a few 53 low bits dedicated to flags. Note that TASK_PENDING and WAS_LAST can 54 share space because WAS_LAST is never stored back to generation. */ 55 #define BAR_TASK_PENDING 1 56 #define BAR_WAS_LAST 1 57 #define BAR_WAITING_FOR_TASK 2 58 #define BAR_CANCELLED 4 59 #define BAR_INCR 8 60 61 extern void gomp_barrier_init (gomp_barrier_t *, unsigned); 62 extern void gomp_barrier_reinit (gomp_barrier_t *, unsigned); 63 extern void gomp_barrier_destroy (gomp_barrier_t *); 64 65 extern void gomp_barrier_wait (gomp_barrier_t *); 66 extern void gomp_barrier_wait_end (gomp_barrier_t *, gomp_barrier_state_t); 67 extern void gomp_team_barrier_wait (gomp_barrier_t *); 68 extern void gomp_team_barrier_wait_end (gomp_barrier_t *, 69 gomp_barrier_state_t); 70 extern bool gomp_team_barrier_wait_cancel (gomp_barrier_t *); 71 extern bool gomp_team_barrier_wait_cancel_end (gomp_barrier_t *, 72 gomp_barrier_state_t); 73 extern void gomp_team_barrier_wake (gomp_barrier_t *, int); 74 struct gomp_team; 75 extern void gomp_team_barrier_cancel (struct gomp_team *); 76 77 static inline gomp_barrier_state_t 78 gomp_barrier_wait_start (gomp_barrier_t *bar) 79 { 80 unsigned int ret; 81 gomp_mutex_lock (&bar->mutex1); 82 ret = bar->generation & (-BAR_INCR | BAR_CANCELLED); 83 if (++bar->arrived == bar->total) 84 ret |= BAR_WAS_LAST; 85 return ret; 86 } 87 88 static inline gomp_barrier_state_t 89 gomp_barrier_wait_cancel_start (gomp_barrier_t *bar) 90 { 91 unsigned int ret; 92 gomp_mutex_lock (&bar->mutex1); 93 ret = bar->generation & (-BAR_INCR | BAR_CANCELLED); 94 if (ret & BAR_CANCELLED) 95 return ret; 96 if (++bar->arrived == bar->total) 97 ret |= BAR_WAS_LAST; 98 return ret; 99 } 100 101 static inline void 102 gomp_team_barrier_wait_final (gomp_barrier_t *bar) 103 { 104 gomp_team_barrier_wait (bar); 105 } 106 107 static inline bool 108 gomp_barrier_last_thread (gomp_barrier_state_t state) 109 { 110 return state & BAR_WAS_LAST; 111 } 112 113 static inline void 114 gomp_barrier_wait_last (gomp_barrier_t *bar) 115 { 116 gomp_barrier_wait (bar); 117 } 118 119 /* All the inlines below must be called with team->task_lock 120 held. */ 121 122 static inline void 123 gomp_team_barrier_set_task_pending (gomp_barrier_t *bar) 124 { 125 bar->generation |= BAR_TASK_PENDING; 126 } 127 128 static inline void 129 gomp_team_barrier_clear_task_pending (gomp_barrier_t *bar) 130 { 131 bar->generation &= ~BAR_TASK_PENDING; 132 } 133 134 static inline void 135 gomp_team_barrier_set_waiting_for_tasks (gomp_barrier_t *bar) 136 { 137 bar->generation |= BAR_WAITING_FOR_TASK; 138 } 139 140 static inline bool 141 gomp_team_barrier_waiting_for_tasks (gomp_barrier_t *bar) 142 { 143 return (bar->generation & BAR_WAITING_FOR_TASK) != 0; 144 } 145 146 static inline bool 147 gomp_team_barrier_cancelled (gomp_barrier_t *bar) 148 { 149 return __builtin_expect ((bar->generation & BAR_CANCELLED) != 0, 0); 150 } 151 152 static inline void 153 gomp_team_barrier_done (gomp_barrier_t *bar, gomp_barrier_state_t state) 154 { 155 bar->generation = (state & -BAR_INCR) + BAR_INCR; 156 } 157 158 #endif /* GOMP_BARRIER_H */ 159