1 /*
2 * Copyright (c) 2016, Alliance for Open Media. All rights reserved
3 *
4 * This source code is subject to the terms of the BSD 2 Clause License and
5 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
6 * was not distributed with this source code in the LICENSE file, you can
7 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
8 * Media Patent License 1.0 was not distributed with this source code in the
9 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10 */
11 //
12 // Multi-threaded worker
13 //
14 // Original source:
15 // https://chromium.googlesource.com/webm/libwebp
16
17 // Enable GNU extensions in glibc so that we can call pthread_setname_np().
18 // This must be before any #include statements.
19 #ifndef _GNU_SOURCE
20 #define _GNU_SOURCE
21 #endif
22
23 #include <assert.h>
24 #include <string.h> // for memset()
25
26 #include "aom_mem/aom_mem.h"
27 #include "aom_util/aom_thread.h"
28
29 #if CONFIG_MULTITHREAD
30
31 struct AVxWorkerImpl {
32 pthread_mutex_t mutex_;
33 pthread_cond_t condition_;
34 pthread_t thread_;
35 };
36
37 //------------------------------------------------------------------------------
38
39 static void execute(AVxWorker *const worker); // Forward declaration.
40
thread_loop(void * ptr)41 static THREADFN thread_loop(void *ptr) {
42 AVxWorker *const worker = (AVxWorker *)ptr;
43 #ifdef __APPLE__
44 if (worker->thread_name != NULL) {
45 // Apple's version of pthread_setname_np takes one argument and operates on
46 // the current thread only. The maximum size of the thread_name buffer was
47 // noted in the Chromium source code and was confirmed by experiments. If
48 // thread_name is too long, pthread_setname_np returns -1 with errno
49 // ENAMETOOLONG (63).
50 char thread_name[64];
51 strncpy(thread_name, worker->thread_name, sizeof(thread_name) - 1);
52 thread_name[sizeof(thread_name) - 1] = '\0';
53 pthread_setname_np(thread_name);
54 }
55 #elif (defined(__GLIBC__) && !defined(__GNU__)) || defined(__BIONIC__)
56 if (worker->thread_name != NULL) {
57 // Linux and Android require names (with nul) fit in 16 chars, otherwise
58 // pthread_setname_np() returns ERANGE (34).
59 char thread_name[16];
60 strncpy(thread_name, worker->thread_name, sizeof(thread_name) - 1);
61 thread_name[sizeof(thread_name) - 1] = '\0';
62 pthread_setname_np(pthread_self(), thread_name);
63 }
64 #endif
65 int done = 0;
66 while (!done) {
67 pthread_mutex_lock(&worker->impl_->mutex_);
68 while (worker->status_ == OK) { // wait in idling mode
69 pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
70 }
71 if (worker->status_ == WORK) {
72 execute(worker);
73 worker->status_ = OK;
74 } else if (worker->status_ == NOT_OK) { // finish the worker
75 done = 1;
76 }
77 // signal to the main thread that we're done (for sync())
78 pthread_cond_signal(&worker->impl_->condition_);
79 pthread_mutex_unlock(&worker->impl_->mutex_);
80 }
81 return THREAD_RETURN(NULL); // Thread is finished
82 }
83
84 // main thread state control
change_state(AVxWorker * const worker,AVxWorkerStatus new_status)85 static void change_state(AVxWorker *const worker, AVxWorkerStatus new_status) {
86 // No-op when attempting to change state on a thread that didn't come up.
87 // Checking status_ without acquiring the lock first would result in a data
88 // race.
89 if (worker->impl_ == NULL) return;
90
91 pthread_mutex_lock(&worker->impl_->mutex_);
92 if (worker->status_ >= OK) {
93 // wait for the worker to finish
94 while (worker->status_ != OK) {
95 pthread_cond_wait(&worker->impl_->condition_, &worker->impl_->mutex_);
96 }
97 // assign new status and release the working thread if needed
98 if (new_status != OK) {
99 worker->status_ = new_status;
100 pthread_cond_signal(&worker->impl_->condition_);
101 }
102 }
103 pthread_mutex_unlock(&worker->impl_->mutex_);
104 }
105
106 #endif // CONFIG_MULTITHREAD
107
108 //------------------------------------------------------------------------------
109
init(AVxWorker * const worker)110 static void init(AVxWorker *const worker) {
111 memset(worker, 0, sizeof(*worker));
112 worker->status_ = NOT_OK;
113 }
114
sync(AVxWorker * const worker)115 static int sync(AVxWorker *const worker) {
116 #if CONFIG_MULTITHREAD
117 change_state(worker, OK);
118 #endif
119 assert(worker->status_ <= OK);
120 return !worker->had_error;
121 }
122
reset(AVxWorker * const worker)123 static int reset(AVxWorker *const worker) {
124 int ok = 1;
125 worker->had_error = 0;
126 if (worker->status_ < OK) {
127 #if CONFIG_MULTITHREAD
128 worker->impl_ = (AVxWorkerImpl *)aom_calloc(1, sizeof(*worker->impl_));
129 if (worker->impl_ == NULL) {
130 return 0;
131 }
132 if (pthread_mutex_init(&worker->impl_->mutex_, NULL)) {
133 goto Error;
134 }
135 if (pthread_cond_init(&worker->impl_->condition_, NULL)) {
136 pthread_mutex_destroy(&worker->impl_->mutex_);
137 goto Error;
138 }
139 pthread_mutex_lock(&worker->impl_->mutex_);
140 ok = !pthread_create(&worker->impl_->thread_, NULL, thread_loop, worker);
141 if (ok) worker->status_ = OK;
142 pthread_mutex_unlock(&worker->impl_->mutex_);
143 if (!ok) {
144 pthread_mutex_destroy(&worker->impl_->mutex_);
145 pthread_cond_destroy(&worker->impl_->condition_);
146 Error:
147 aom_free(worker->impl_);
148 worker->impl_ = NULL;
149 return 0;
150 }
151 #else
152 worker->status_ = OK;
153 #endif
154 } else if (worker->status_ > OK) {
155 ok = sync(worker);
156 }
157 assert(!ok || (worker->status_ == OK));
158 return ok;
159 }
160
execute(AVxWorker * const worker)161 static void execute(AVxWorker *const worker) {
162 if (worker->hook != NULL) {
163 worker->had_error |= !worker->hook(worker->data1, worker->data2);
164 }
165 }
166
launch(AVxWorker * const worker)167 static void launch(AVxWorker *const worker) {
168 #if CONFIG_MULTITHREAD
169 change_state(worker, WORK);
170 #else
171 execute(worker);
172 #endif
173 }
174
end(AVxWorker * const worker)175 static void end(AVxWorker *const worker) {
176 #if CONFIG_MULTITHREAD
177 if (worker->impl_ != NULL) {
178 change_state(worker, NOT_OK);
179 pthread_join(worker->impl_->thread_, NULL);
180 pthread_mutex_destroy(&worker->impl_->mutex_);
181 pthread_cond_destroy(&worker->impl_->condition_);
182 aom_free(worker->impl_);
183 worker->impl_ = NULL;
184 }
185 #else
186 worker->status_ = NOT_OK;
187 assert(worker->impl_ == NULL);
188 #endif
189 assert(worker->status_ == NOT_OK);
190 }
191
192 //------------------------------------------------------------------------------
193
194 static AVxWorkerInterface g_worker_interface = { init, reset, sync,
195 launch, execute, end };
196
aom_set_worker_interface(const AVxWorkerInterface * const winterface)197 int aom_set_worker_interface(const AVxWorkerInterface *const winterface) {
198 if (winterface == NULL || winterface->init == NULL ||
199 winterface->reset == NULL || winterface->sync == NULL ||
200 winterface->launch == NULL || winterface->execute == NULL ||
201 winterface->end == NULL) {
202 return 0;
203 }
204 g_worker_interface = *winterface;
205 return 1;
206 }
207
aom_get_worker_interface(void)208 const AVxWorkerInterface *aom_get_worker_interface(void) {
209 return &g_worker_interface;
210 }
211
212 //------------------------------------------------------------------------------
213