2 * This file is part of Libav.
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.
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.
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
21 * Libavfilter multithreading support
26 #include "libavutil/common.h"
27 #include "libavutil/cpu.h"
28 #include "libavutil/mem.h"
37 #include "compat/w32pthreads.h"
40 typedef struct ThreadContext {
45 avfilter_action_func *func;
47 /* per-execute perameters */
54 pthread_cond_t last_job_cond;
55 pthread_cond_t current_job_cond;
56 pthread_mutex_t current_job_lock;
58 unsigned int current_execute;
62 static void* attribute_align_arg worker(void *v)
65 int our_job = c->nb_jobs;
66 int nb_threads = c->nb_threads;
67 unsigned int last_execute = 0;
70 pthread_mutex_lock(&c->current_job_lock);
71 self_id = c->current_job++;
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);
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;
83 pthread_mutex_unlock(&c->current_job_lock);
87 pthread_mutex_unlock(&c->current_job_lock);
89 c->rets[our_job % c->nb_rets] = c->func(c->ctx, c->arg, our_job, c->nb_jobs);
91 pthread_mutex_lock(&c->current_job_lock);
92 our_job = c->current_job++;
96 static void slice_thread_uninit(ThreadContext *c)
100 pthread_mutex_lock(&c->current_job_lock);
102 pthread_cond_broadcast(&c->current_job_cond);
103 pthread_mutex_unlock(&c->current_job_lock);
105 for (i = 0; i < c->nb_threads; i++)
106 pthread_join(c->workers[i], NULL);
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);
114 static void slice_thread_park_workers(ThreadContext *c)
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);
121 static int thread_execute(AVFilterContext *ctx, avfilter_action_func *func,
122 void *arg, int *ret, int nb_jobs)
124 ThreadContext *c = ctx->graph->internal->thread;
130 pthread_mutex_lock(&c->current_job_lock);
132 c->current_job = c->nb_threads;
133 c->nb_jobs = nb_jobs;
139 c->nb_rets = nb_jobs;
141 c->rets = &dummy_ret;
144 c->current_execute++;
146 pthread_cond_broadcast(&c->current_job_cond);
148 slice_thread_park_workers(c);
153 static int thread_init_internal(ThreadContext *c, int 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
162 nb_threads = nb_cpus + 1;
170 c->nb_threads = nb_threads;
171 c->workers = av_mallocz(sizeof(*c->workers) * nb_threads);
173 return AVERROR(ENOMEM);
179 pthread_cond_init(&c->current_job_cond, NULL);
180 pthread_cond_init(&c->last_job_cond, NULL);
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);
187 pthread_mutex_unlock(&c->current_job_lock);
189 slice_thread_uninit(c);
194 slice_thread_park_workers(c);
196 return c->nb_threads;
199 int ff_graph_thread_init(AVFilterGraph *graph)
207 if (graph->nb_threads == 1) {
208 graph->thread_type = 0;
212 graph->internal->thread = av_mallocz(sizeof(ThreadContext));
213 if (!graph->internal->thread)
214 return AVERROR(ENOMEM);
216 ret = thread_init_internal(graph->internal->thread, graph->nb_threads);
218 av_freep(&graph->internal->thread);
219 graph->thread_type = 0;
220 graph->nb_threads = 1;
221 return (ret < 0) ? ret : 0;
223 graph->nb_threads = ret;
225 graph->internal->thread_execute = thread_execute;
230 void ff_graph_thread_free(AVFilterGraph *graph)
232 if (graph->internal->thread)
233 slice_thread_uninit(graph->internal->thread);
234 av_freep(&graph->internal->thread);