1/* 2 * 3 * This file is part of FFmpeg. 4 * 5 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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_OS2THREADS 38#include "compat/os2threads.h" 39#elif HAVE_W32THREADS 40#include "compat/w32pthreads.h" 41#endif 42 43typedef struct ThreadContext { 44 AVFilterGraph *graph; 45 46 int nb_threads; 47 pthread_t *workers; 48 avfilter_action_func *func; 49 50 /* per-execute perameters */ 51 AVFilterContext *ctx; 52 void *arg; 53 int *rets; 54 int nb_rets; 55 int nb_jobs; 56 57 pthread_cond_t last_job_cond; 58 pthread_cond_t current_job_cond; 59 pthread_mutex_t current_job_lock; 60 int current_job; 61 unsigned int current_execute; 62 int done; 63} ThreadContext; 64 65static void* attribute_align_arg worker(void *v) 66{ 67 ThreadContext *c = v; 68 int our_job = c->nb_jobs; 69 int nb_threads = c->nb_threads; 70 unsigned int last_execute = 0; 71 int self_id; 72 73 pthread_mutex_lock(&c->current_job_lock); 74 self_id = c->current_job++; 75 for (;;) { 76 while (our_job >= c->nb_jobs) { 77 if (c->current_job == nb_threads + c->nb_jobs) 78 pthread_cond_signal(&c->last_job_cond); 79 80 while (last_execute == c->current_execute && !c->done) 81 pthread_cond_wait(&c->current_job_cond, &c->current_job_lock); 82 last_execute = c->current_execute; 83 our_job = self_id; 84 85 if (c->done) { 86 pthread_mutex_unlock(&c->current_job_lock); 87 return NULL; 88 } 89 } 90 pthread_mutex_unlock(&c->current_job_lock); 91 92 c->rets[our_job % c->nb_rets] = c->func(c->ctx, c->arg, our_job, c->nb_jobs); 93 94 pthread_mutex_lock(&c->current_job_lock); 95 our_job = c->current_job++; 96 } 97} 98 99static void slice_thread_uninit(ThreadContext *c) 100{ 101 int i; 102 103 pthread_mutex_lock(&c->current_job_lock); 104 c->done = 1; 105 pthread_cond_broadcast(&c->current_job_cond); 106 pthread_mutex_unlock(&c->current_job_lock); 107 108 for (i = 0; i < c->nb_threads; i++) 109 pthread_join(c->workers[i], NULL); 110 111 pthread_mutex_destroy(&c->current_job_lock); 112 pthread_cond_destroy(&c->current_job_cond); 113 pthread_cond_destroy(&c->last_job_cond); 114 av_freep(&c->workers); 115} 116 117static void slice_thread_park_workers(ThreadContext *c) 118{ 119 while (c->current_job != c->nb_threads + c->nb_jobs) 120 pthread_cond_wait(&c->last_job_cond, &c->current_job_lock); 121 pthread_mutex_unlock(&c->current_job_lock); 122} 123 124static int thread_execute(AVFilterContext *ctx, avfilter_action_func *func, 125 void *arg, int *ret, int nb_jobs) 126{ 127 ThreadContext *c = ctx->graph->internal->thread; 128 int dummy_ret; 129 130 if (nb_jobs <= 0) 131 return 0; 132 133 pthread_mutex_lock(&c->current_job_lock); 134 135 c->current_job = c->nb_threads; 136 c->nb_jobs = nb_jobs; 137 c->ctx = ctx; 138 c->arg = arg; 139 c->func = func; 140 if (ret) { 141 c->rets = ret; 142 c->nb_rets = nb_jobs; 143 } else { 144 c->rets = &dummy_ret; 145 c->nb_rets = 1; 146 } 147 c->current_execute++; 148 149 pthread_cond_broadcast(&c->current_job_cond); 150 151 slice_thread_park_workers(c); 152 153 return 0; 154} 155 156static int thread_init_internal(ThreadContext *c, int nb_threads) 157{ 158 int i, ret; 159 160 if (!nb_threads) { 161 int nb_cpus = av_cpu_count(); 162 // use number of cores + 1 as thread count if there is more than one 163 if (nb_cpus > 1) 164 nb_threads = nb_cpus + 1; 165 else 166 nb_threads = 1; 167 } 168 169 if (nb_threads <= 1) 170 return 1; 171 172 c->nb_threads = nb_threads; 173 c->workers = av_mallocz_array(sizeof(*c->workers), nb_threads); 174 if (!c->workers) 175 return AVERROR(ENOMEM); 176 177 c->current_job = 0; 178 c->nb_jobs = 0; 179 c->done = 0; 180 181 pthread_cond_init(&c->current_job_cond, NULL); 182 pthread_cond_init(&c->last_job_cond, NULL); 183 184 pthread_mutex_init(&c->current_job_lock, NULL); 185 pthread_mutex_lock(&c->current_job_lock); 186 for (i = 0; i < nb_threads; i++) { 187 ret = pthread_create(&c->workers[i], NULL, worker, c); 188 if (ret) { 189 pthread_mutex_unlock(&c->current_job_lock); 190 c->nb_threads = i; 191 slice_thread_uninit(c); 192 return AVERROR(ret); 193 } 194 } 195 196 slice_thread_park_workers(c); 197 198 return c->nb_threads; 199} 200 201int ff_graph_thread_init(AVFilterGraph *graph) 202{ 203 int ret; 204 205#if HAVE_W32THREADS 206 w32thread_init(); 207#endif 208 209 if (graph->nb_threads == 1) { 210 graph->thread_type = 0; 211 return 0; 212 } 213 214 graph->internal->thread = av_mallocz(sizeof(ThreadContext)); 215 if (!graph->internal->thread) 216 return AVERROR(ENOMEM); 217 218 ret = thread_init_internal(graph->internal->thread, graph->nb_threads); 219 if (ret <= 1) { 220 av_freep(&graph->internal->thread); 221 graph->thread_type = 0; 222 graph->nb_threads = 1; 223 return (ret < 0) ? ret : 0; 224 } 225 graph->nb_threads = ret; 226 227 graph->internal->thread_execute = thread_execute; 228 229 return 0; 230} 231 232void ff_graph_thread_free(AVFilterGraph *graph) 233{ 234 if (graph->internal->thread) 235 slice_thread_uninit(graph->internal->thread); 236 av_freep(&graph->internal->thread); 237} 238