af_compand: make sure request_frame always outputs at least one frame
[ffmpeg.git] / libavfilter / pthread.c
1 /*
2  *
3  * This file is part of Libav.
4  *
5  * Libav is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * Libav is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with Libav; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18  */
19
20 /**
21  * @file
22  * Libavfilter multithreading support
23  */
24
25 #include "config.h"
26
27 #include "libavutil/common.h"
28 #include "libavutil/cpu.h"
29 #include "libavutil/mem.h"
30
31 #include "avfilter.h"
32 #include "internal.h"
33 #include "thread.h"
34
35 #if HAVE_PTHREADS
36 #include <pthread.h>
37 #elif HAVE_W32THREADS
38 #include "compat/w32pthreads.h"
39 #endif
40
41 typedef struct ThreadContext {
42     AVFilterGraph *graph;
43
44     int nb_threads;
45     pthread_t *workers;
46     avfilter_action_func *func;
47
48     /* per-execute perameters */
49     AVFilterContext *ctx;
50     void *arg;
51     int   *rets;
52     int nb_rets;
53     int nb_jobs;
54
55     pthread_cond_t last_job_cond;
56     pthread_cond_t current_job_cond;
57     pthread_mutex_t current_job_lock;
58     int current_job;
59     unsigned int current_execute;
60     int done;
61 } ThreadContext;
62
63 static void* attribute_align_arg worker(void *v)
64 {
65     ThreadContext *c = v;
66     int our_job      = c->nb_jobs;
67     int nb_threads   = c->nb_threads;
68     unsigned int last_execute = 0;
69     int self_id;
70
71     pthread_mutex_lock(&c->current_job_lock);
72     self_id = c->current_job++;
73     for (;;) {
74         while (our_job >= c->nb_jobs) {
75             if (c->current_job == nb_threads + c->nb_jobs)
76                 pthread_cond_signal(&c->last_job_cond);
77
78             while (last_execute == c->current_execute && !c->done)
79                 pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
80             last_execute = c->current_execute;
81             our_job = self_id;
82
83             if (c->done) {
84                 pthread_mutex_unlock(&c->current_job_lock);
85                 return NULL;
86             }
87         }
88         pthread_mutex_unlock(&c->current_job_lock);
89
90         c->rets[our_job % c->nb_rets] = c->func(c->ctx, c->arg, our_job, c->nb_jobs);
91
92         pthread_mutex_lock(&c->current_job_lock);
93         our_job = c->current_job++;
94     }
95 }
96
97 static void slice_thread_uninit(ThreadContext *c)
98 {
99     int i;
100
101     pthread_mutex_lock(&c->current_job_lock);
102     c->done = 1;
103     pthread_cond_broadcast(&c->current_job_cond);
104     pthread_mutex_unlock(&c->current_job_lock);
105
106     for (i = 0; i < c->nb_threads; i++)
107          pthread_join(c->workers[i], NULL);
108
109     pthread_mutex_destroy(&c->current_job_lock);
110     pthread_cond_destroy(&c->current_job_cond);
111     pthread_cond_destroy(&c->last_job_cond);
112     av_freep(&c->workers);
113 }
114
115 static void slice_thread_park_workers(ThreadContext *c)
116 {
117     while (c->current_job != c->nb_threads + c->nb_jobs)
118         pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
119     pthread_mutex_unlock(&c->current_job_lock);
120 }
121
122 static int thread_execute(AVFilterContext *ctx, avfilter_action_func *func,
123                           void *arg, int *ret, int nb_jobs)
124 {
125     ThreadContext *c = ctx->graph->internal->thread;
126     int dummy_ret;
127
128     if (nb_jobs <= 0)
129         return 0;
130
131     pthread_mutex_lock(&c->current_job_lock);
132
133     c->current_job = c->nb_threads;
134     c->nb_jobs     = nb_jobs;
135     c->ctx         = ctx;
136     c->arg         = arg;
137     c->func        = func;
138     if (ret) {
139         c->rets    = ret;
140         c->nb_rets = nb_jobs;
141     } else {
142         c->rets    = &dummy_ret;
143         c->nb_rets = 1;
144     }
145     c->current_execute++;
146
147     pthread_cond_broadcast(&c->current_job_cond);
148
149     slice_thread_park_workers(c);
150
151     return 0;
152 }
153
154 static int thread_init_internal(ThreadContext *c, int nb_threads)
155 {
156     int i, ret;
157
158     if (!nb_threads) {
159         int nb_cpus = av_cpu_count();
160         av_log(c->graph, AV_LOG_DEBUG, "Detected %d logical cores.\n", nb_cpus);
161         // use number of cores + 1 as thread count if there is more than one
162         if (nb_cpus > 1)
163             nb_threads = nb_cpus + 1;
164         else
165             nb_threads = 1;
166     }
167
168     if (nb_threads <= 1)
169         return 1;
170
171     c->nb_threads = nb_threads;
172     c->workers = av_mallocz(sizeof(*c->workers) * nb_threads);
173     if (!c->workers)
174         return AVERROR(ENOMEM);
175
176     c->current_job = 0;
177     c->nb_jobs     = 0;
178     c->done        = 0;
179
180     pthread_cond_init(&c->current_job_cond, NULL);
181     pthread_cond_init(&c->last_job_cond,    NULL);
182
183     pthread_mutex_init(&c->current_job_lock, NULL);
184     pthread_mutex_lock(&c->current_job_lock);
185     for (i = 0; i < nb_threads; i++) {
186         ret = pthread_create(&c->workers[i], NULL, worker, c);
187         if (ret) {
188            pthread_mutex_unlock(&c->current_job_lock);
189            c->nb_threads = i;
190            slice_thread_uninit(c);
191            return AVERROR(ret);
192         }
193     }
194
195     slice_thread_park_workers(c);
196
197     return c->nb_threads;
198 }
199
200 int ff_graph_thread_init(AVFilterGraph *graph)
201 {
202     int ret;
203
204 #if HAVE_W32THREADS
205     w32thread_init();
206 #endif
207
208     if (graph->nb_threads == 1) {
209         graph->thread_type = 0;
210         return 0;
211     }
212
213     graph->internal->thread = av_mallocz(sizeof(ThreadContext));
214     if (!graph->internal->thread)
215         return AVERROR(ENOMEM);
216
217     ret = thread_init_internal(graph->internal->thread, graph->nb_threads);
218     if (ret <= 1) {
219         av_freep(&graph->internal->thread);
220         graph->thread_type = 0;
221         graph->nb_threads  = 1;
222         return (ret < 0) ? ret : 0;
223     }
224     graph->nb_threads = ret;
225
226     graph->internal->thread_execute = thread_execute;
227
228     return 0;
229 }
230
231 void ff_graph_thread_free(AVFilterGraph *graph)
232 {
233     if (graph->internal->thread)
234         slice_thread_uninit(graph->internal->thread);
235     av_freep(&graph->internal->thread);
236 }