vaapi_h264: Add constant-bitrate encode support
[ffmpeg.git] / libavfilter / pthread.c
1 /*
2  * This file is part of Libav.
3  *
4  * Libav is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Lesser General Public
6  * License as published by the Free Software Foundation; either
7  * version 2.1 of the License, or (at your option) any later version.
8  *
9  * Libav is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12  * Lesser General Public License for more details.
13  *
14  * You should have received a copy of the GNU Lesser General Public
15  * License along with Libav; if not, write to the Free Software
16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17  */
18
19 /**
20  * @file
21  * Libavfilter multithreading support
22  */
23
24 #include "config.h"
25
26 #include "libavutil/common.h"
27 #include "libavutil/cpu.h"
28 #include "libavutil/mem.h"
29
30 #include "avfilter.h"
31 #include "internal.h"
32 #include "thread.h"
33
34 #if HAVE_PTHREADS
35 #include <pthread.h>
36 #elif HAVE_W32THREADS
37 #include "compat/w32pthreads.h"
38 #endif
39
40 typedef struct ThreadContext {
41     AVFilterGraph *graph;
42
43     int nb_threads;
44     pthread_t *workers;
45     avfilter_action_func *func;
46
47     /* per-execute perameters */
48     AVFilterContext *ctx;
49     void *arg;
50     int   *rets;
51     int nb_rets;
52     int nb_jobs;
53
54     pthread_cond_t last_job_cond;
55     pthread_cond_t current_job_cond;
56     pthread_mutex_t current_job_lock;
57     int current_job;
58     unsigned int current_execute;
59     int done;
60 } ThreadContext;
61
62 static void* attribute_align_arg worker(void *v)
63 {
64     ThreadContext *c = v;
65     int our_job      = c->nb_jobs;
66     int nb_threads   = c->nb_threads;
67     unsigned int last_execute = 0;
68     int self_id;
69
70     pthread_mutex_lock(&c->current_job_lock);
71     self_id = c->current_job++;
72     for (;;) {
73         while (our_job >= c->nb_jobs) {
74             if (c->current_job == nb_threads + c->nb_jobs)
75                 pthread_cond_signal(&c->last_job_cond);
76
77             while (last_execute == c->current_execute && !c->done)
78                 pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
79             last_execute = c->current_execute;
80             our_job = self_id;
81
82             if (c->done) {
83                 pthread_mutex_unlock(&c->current_job_lock);
84                 return NULL;
85             }
86         }
87         pthread_mutex_unlock(&c->current_job_lock);
88
89         c->rets[our_job % c->nb_rets] = c->func(c->ctx, c->arg, our_job, c->nb_jobs);
90
91         pthread_mutex_lock(&c->current_job_lock);
92         our_job = c->current_job++;
93     }
94 }
95
96 static void slice_thread_uninit(ThreadContext *c)
97 {
98     int i;
99
100     pthread_mutex_lock(&c->current_job_lock);
101     c->done = 1;
102     pthread_cond_broadcast(&c->current_job_cond);
103     pthread_mutex_unlock(&c->current_job_lock);
104
105     for (i = 0; i < c->nb_threads; i++)
106          pthread_join(c->workers[i], NULL);
107
108     pthread_mutex_destroy(&c->current_job_lock);
109     pthread_cond_destroy(&c->current_job_cond);
110     pthread_cond_destroy(&c->last_job_cond);
111     av_freep(&c->workers);
112 }
113
114 static void slice_thread_park_workers(ThreadContext *c)
115 {
116     while (c->current_job != c->nb_threads + c->nb_jobs)
117         pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
118     pthread_mutex_unlock(&c->current_job_lock);
119 }
120
121 static int thread_execute(AVFilterContext *ctx, avfilter_action_func *func,
122                           void *arg, int *ret, int nb_jobs)
123 {
124     ThreadContext *c = ctx->graph->internal->thread;
125     int dummy_ret;
126
127     if (nb_jobs <= 0)
128         return 0;
129
130     pthread_mutex_lock(&c->current_job_lock);
131
132     c->current_job = c->nb_threads;
133     c->nb_jobs     = nb_jobs;
134     c->ctx         = ctx;
135     c->arg         = arg;
136     c->func        = func;
137     if (ret) {
138         c->rets    = ret;
139         c->nb_rets = nb_jobs;
140     } else {
141         c->rets    = &dummy_ret;
142         c->nb_rets = 1;
143     }
144     c->current_execute++;
145
146     pthread_cond_broadcast(&c->current_job_cond);
147
148     slice_thread_park_workers(c);
149
150     return 0;
151 }
152
153 static int thread_init_internal(ThreadContext *c, int nb_threads)
154 {
155     int i, ret;
156
157     if (!nb_threads) {
158         int nb_cpus = av_cpu_count();
159         av_log(c->graph, AV_LOG_DEBUG, "Detected %d logical cores.\n", nb_cpus);
160         // use number of cores + 1 as thread count if there is more than one
161         if (nb_cpus > 1)
162             nb_threads = nb_cpus + 1;
163         else
164             nb_threads = 1;
165     }
166
167     if (nb_threads <= 1)
168         return 1;
169
170     c->nb_threads = nb_threads;
171     c->workers = av_mallocz(sizeof(*c->workers) * nb_threads);
172     if (!c->workers)
173         return AVERROR(ENOMEM);
174
175     c->current_job = 0;
176     c->nb_jobs     = 0;
177     c->done        = 0;
178
179     pthread_cond_init(&c->current_job_cond, NULL);
180     pthread_cond_init(&c->last_job_cond,    NULL);
181
182     pthread_mutex_init(&c->current_job_lock, NULL);
183     pthread_mutex_lock(&c->current_job_lock);
184     for (i = 0; i < nb_threads; i++) {
185         ret = pthread_create(&c->workers[i], NULL, worker, c);
186         if (ret) {
187            pthread_mutex_unlock(&c->current_job_lock);
188            c->nb_threads = i;
189            slice_thread_uninit(c);
190            return AVERROR(ret);
191         }
192     }
193
194     slice_thread_park_workers(c);
195
196     return c->nb_threads;
197 }
198
199 int ff_graph_thread_init(AVFilterGraph *graph)
200 {
201     int ret;
202
203 #if HAVE_W32THREADS
204     w32thread_init();
205 #endif
206
207     if (graph->nb_threads == 1) {
208         graph->thread_type = 0;
209         return 0;
210     }
211
212     graph->internal->thread = av_mallocz(sizeof(ThreadContext));
213     if (!graph->internal->thread)
214         return AVERROR(ENOMEM);
215
216     ret = thread_init_internal(graph->internal->thread, graph->nb_threads);
217     if (ret <= 1) {
218         av_freep(&graph->internal->thread);
219         graph->thread_type = 0;
220         graph->nb_threads  = 1;
221         return (ret < 0) ? ret : 0;
222     }
223     graph->nb_threads = ret;
224
225     graph->internal->thread_execute = thread_execute;
226
227     return 0;
228 }
229
230 void ff_graph_thread_free(AVFilterGraph *graph)
231 {
232     if (graph->internal->thread)
233         slice_thread_uninit(graph->internal->thread);
234     av_freep(&graph->internal->thread);
235 }