| 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 | |
| 43 | typedef 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 | |
| 65 | static 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 | |
| 99 | static 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 | |
| 117 | static 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 | |
| 124 | static 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 | |
| 156 | static 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 | |
| 201 | int 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 | |
| 232 | void 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 | } |