1 /* Copyright (C) 2015-2023 Free Software Foundation, Inc.
2 Contributed by Sebastian Huber <sebastian.huber@embedded-brains.de>.
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 RTEMS implementation of the thread pool management
27 for libgomp. This type is private to the library. */
28
29 #ifndef GOMP_POOL_H
30 #define GOMP_POOL_H 1
31
32 #include "libgomp.h"
33 #include <sys/lock.h>
34 #include <string.h>
35
36 /* For each scheduler instance there may be a thread pool reservoir
37 to limit the number of thread pools used by the OpenMP master threads of this
38 scheduler instance. The reservoirs are configured via the
39 GOMP_RTEMS_THREAD_POOLS environment variable. */
40 struct gomp_thread_pool_reservoir {
41 gomp_sem_t available;
42 pthread_spinlock_t lock;
43 size_t index;
44 int priority;
45 struct gomp_thread_pool *pools[];
46 };
47
48 struct gomp_tls_rtems_data {
49 struct gomp_thread_pool_reservoir *thread_pool_reservoir;
50 };
51
52 extern struct gomp_thread_pool_reservoir **gomp_thread_pool_reservoirs;
53
54 extern __thread struct gomp_tls_rtems_data gomp_tls_rtems_data;
55
56 static inline struct gomp_thread_pool_reservoir *
57 gomp_get_thread_pool_reservoir (void)
58 {
59 struct gomp_thread_pool_reservoir *res =
60 gomp_tls_rtems_data.thread_pool_reservoir;
61
62 if (res == NULL && gomp_thread_pool_reservoirs != NULL)
63 {
64 struct gomp_thread *thr = gomp_thread ();
65 thr->thread_pool = gomp_malloc_cleared (sizeof (*thr->thread_pool));
66 res = gomp_thread_pool_reservoirs[_Sched_Index ()];
67 gomp_tls_rtems_data.thread_pool_reservoir = res;
68 }
69
70 return res;
71 }
72
73 static inline struct gomp_thread_pool *
74 gomp_get_own_thread_pool (struct gomp_thread *thr, unsigned nthreads)
75 {
76 struct gomp_thread_pool *pool = thr->thread_pool;
77 if (__builtin_expect (pool == NULL, 0))
78 {
79 pool = gomp_malloc_cleared (sizeof (*pool));
80 pool->threads_busy = nthreads;
81 thr->thread_pool = pool;
82 }
83 return pool;
84 }
85
86 static inline struct gomp_thread_pool *
87 gomp_get_thread_pool (struct gomp_thread *thr, unsigned nthreads)
88 {
89 struct gomp_thread_pool *pool;
90 struct gomp_thread_pool_reservoir *res;
91
92 if (__builtin_expect (thr->thread_pool == NULL, 0))
93 pthread_setspecific (gomp_thread_destructor, thr);
94
95 res = gomp_get_thread_pool_reservoir ();
96 if (res != NULL)
97 {
98 gomp_sem_wait (&res->available);
99 pthread_spin_lock (&res->lock);
100 pool = res->pools[--res->index];
101 pthread_spin_unlock (&res->lock);
102 pool->threads_busy = nthreads;
103 thr->thread_pool = pool;
104 }
105 else
106 pool = gomp_get_own_thread_pool (thr, nthreads);
107
108 return pool;
109 }
110
111 static inline void
112 gomp_release_thread_pool (struct gomp_thread_pool *pool)
113 {
114 struct gomp_thread_pool_reservoir *res =
115 gomp_tls_rtems_data.thread_pool_reservoir;
116 if (res != NULL)
117 {
118 pthread_spin_lock (&res->lock);
119 res->pools[res->index++] = pool;
120 pthread_spin_unlock (&res->lock);
121 gomp_sem_post (&res->available);
122 }
123 }
124
125 static inline pthread_attr_t *
126 gomp_adjust_thread_attr (pthread_attr_t *attr, pthread_attr_t *mutable_attr)
127 {
128 struct gomp_thread_pool_reservoir *res = gomp_get_thread_pool_reservoir ();
129 if (res != NULL && res->priority > 0)
130 {
131 struct sched_param param;
132 int err;
133 if (attr != mutable_attr)
134 {
135 attr = mutable_attr;
136 pthread_attr_init (attr);
137 }
138 memset (¶m, 0, sizeof (param));
139 param.sched_priority = res->priority;
140 err = pthread_attr_setschedparam (attr, ¶m);
141 if (err != 0)
142 gomp_fatal ("Thread attribute set scheduler parameters failed: %s", strerror (err));
143 err = pthread_attr_setschedpolicy (attr, SCHED_FIFO);
144 if (err != 0)
145 gomp_fatal ("Thread attribute set scheduler policy failed: %s", strerror (err));
146 err = pthread_attr_setinheritsched (attr, PTHREAD_EXPLICIT_SCHED);
147 if (err != 0)
148 gomp_fatal ("Thread attribute set explicit scheduler failed: %s", strerror (err));
149 }
150 return attr;
151 }
152
153 #endif /* GOMP_POOL_H */