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a68ab351 | 1 | /* Copyright (C) 2005, 2008 Free Software Foundation, Inc. |
953ff289 DN |
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 Lesser General Public License as published by | |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
9 | (at your option) 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 Lesser General Public License for | |
14 | more details. | |
15 | ||
16 | You should have received a copy of the GNU Lesser General Public License | |
17 | along with libgomp; see the file COPYING.LIB. If not, write to the | |
18 | Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, | |
19 | MA 02110-1301, USA. */ | |
20 | ||
21 | /* As a special exception, if you link this library with other files, some | |
22 | of which are compiled with GCC, to produce an executable, this library | |
23 | does not by itself cause the resulting executable to be covered by the | |
24 | GNU General Public License. This exception does not however invalidate | |
25 | any other reasons why the executable file might be covered by the GNU | |
26 | General Public License. */ | |
27 | ||
28 | /* This is a Linux specific implementation of a barrier synchronization | |
29 | mechanism for libgomp. This type is private to the library. This | |
30 | implementation uses atomic instructions and the futex syscall. */ | |
31 | ||
32 | #ifndef GOMP_BARRIER_H | |
33 | #define GOMP_BARRIER_H 1 | |
34 | ||
35 | #include "mutex.h" | |
36 | ||
37 | typedef struct | |
38 | { | |
a68ab351 JJ |
39 | /* Make sure total/generation is in a mostly read cacheline, while |
40 | awaited in a separate cacheline. */ | |
41 | unsigned total __attribute__((aligned (64))); | |
42 | unsigned generation; | |
43 | unsigned awaited __attribute__((aligned (64))); | |
953ff289 | 44 | } gomp_barrier_t; |
a68ab351 | 45 | typedef unsigned int gomp_barrier_state_t; |
953ff289 DN |
46 | |
47 | static inline void gomp_barrier_init (gomp_barrier_t *bar, unsigned count) | |
48 | { | |
953ff289 | 49 | bar->total = count; |
a68ab351 | 50 | bar->awaited = count; |
953ff289 DN |
51 | bar->generation = 0; |
52 | } | |
53 | ||
54 | static inline void gomp_barrier_reinit (gomp_barrier_t *bar, unsigned count) | |
55 | { | |
a68ab351 | 56 | __sync_fetch_and_add (&bar->awaited, count - bar->total); |
953ff289 | 57 | bar->total = count; |
953ff289 DN |
58 | } |
59 | ||
60 | static inline void gomp_barrier_destroy (gomp_barrier_t *bar) | |
61 | { | |
953ff289 DN |
62 | } |
63 | ||
64 | extern void gomp_barrier_wait (gomp_barrier_t *); | |
a68ab351 JJ |
65 | extern void gomp_barrier_wait_last (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 void gomp_team_barrier_wake (gomp_barrier_t *, int); | |
953ff289 | 71 | |
a68ab351 JJ |
72 | static inline gomp_barrier_state_t |
73 | gomp_barrier_wait_start (gomp_barrier_t *bar) | |
953ff289 | 74 | { |
a68ab351 JJ |
75 | unsigned int ret = bar->generation & ~3; |
76 | /* Do we need any barrier here or is __sync_add_and_fetch acting | |
77 | as the needed LoadLoad barrier already? */ | |
78 | ret += __sync_add_and_fetch (&bar->awaited, -1) == 0; | |
79 | return ret; | |
80 | } | |
81 | ||
82 | static inline bool | |
83 | gomp_barrier_last_thread (gomp_barrier_state_t state) | |
84 | { | |
85 | return state & 1; | |
86 | } | |
87 | ||
88 | /* All the inlines below must be called with team->task_lock | |
89 | held. */ | |
90 | ||
91 | static inline void | |
92 | gomp_team_barrier_set_task_pending (gomp_barrier_t *bar) | |
93 | { | |
94 | bar->generation |= 1; | |
95 | } | |
96 | ||
97 | static inline void | |
98 | gomp_team_barrier_clear_task_pending (gomp_barrier_t *bar) | |
99 | { | |
100 | bar->generation &= ~1; | |
101 | } | |
102 | ||
103 | static inline void | |
104 | gomp_team_barrier_set_waiting_for_tasks (gomp_barrier_t *bar) | |
105 | { | |
106 | bar->generation |= 2; | |
107 | } | |
108 | ||
109 | static inline bool | |
110 | gomp_team_barrier_waiting_for_tasks (gomp_barrier_t *bar) | |
111 | { | |
112 | return (bar->generation & 2) != 0; | |
113 | } | |
114 | ||
115 | static inline void | |
116 | gomp_team_barrier_done (gomp_barrier_t *bar, gomp_barrier_state_t state) | |
117 | { | |
118 | bar->generation = (state & ~3) + 4; | |
953ff289 DN |
119 | } |
120 | ||
121 | #endif /* GOMP_BARRIER_H */ |