libavcodec/pthread.c

   1 /*
   2  * Copyright (c) 2004 Roman Shaposhnik
   3  *
   4  * Many thanks to Steven M. Schultz for providing clever ideas and
   5  * to Michael Niedermayer <michaelni@gmx.at> for writing initial
   6  * implementation.
   7  *
   8  * This file is part of FFmpeg.
   9  *
  10  * FFmpeg is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Lesser General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2.1 of the License, or (at your option) any later version.
  14  *
  15  * FFmpeg is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public
  21  * License along with FFmpeg; if not, write to the Free Software
  22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  23  */
  24 #include <pthread.h>
  25
  26 #include "avcodec.h"
  27
  28 typedef int (action_func)(AVCodecContext *c, void *arg);
  29 typedef int (action_func2)(AVCodecContext *c, void *arg, int jobnr, int threadnr);
  30
  31 typedef struct ThreadContext {
  32     pthread_t *workers;
  33     action_func *func;
  34     action_func2 *func2;
  35     void *args;
  36     int *rets;
  37     int rets_count;
  38     int job_count;
  39     int job_size;
  40
  41     pthread_cond_t last_job_cond;
  42     pthread_cond_t current_job_cond;
  43     pthread_mutex_t current_job_lock;
  44     int current_job;
  45     int done;
  46 } ThreadContext;
  47
  48 static void* attribute_align_arg worker(void *v)
  49 {
  50     AVCodecContext *avctx = v;
  51     ThreadContext *c = avctx->thread_opaque;
  52     int our_job = c->job_count;
  53     int thread_count = avctx->thread_count;
  54     int self_id;
  55
  56     pthread_mutex_lock(&c->current_job_lock);
  57     self_id = c->current_job++;
  58     for (;;){
  59         while (our_job >= c->job_count) {
  60             if (c->current_job == thread_count + c->job_count)
  61                 pthread_cond_signal(&c->last_job_cond);
  62
  63             pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
  64             our_job = self_id;
  65
  66             if (c->done) {
  67                 pthread_mutex_unlock(&c->current_job_lock);
  68                 return NULL;
  69             }
  70         }
  71         pthread_mutex_unlock(&c->current_job_lock);
  72
  73         c->rets[our_job%c->rets_count] = c->func ? c->func(avctx, (char*)c->args + our_job*c->job_size):
  74                                                    c->func2(avctx, c->args, our_job, self_id);
  75
  76         pthread_mutex_lock(&c->current_job_lock);
  77         our_job = c->current_job++;
  78     }
  79 }
  80
  81 static av_always_inline void avcodec_thread_park_workers(ThreadContext *c, int thread_count)
  82 {
  83     pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
  84     pthread_mutex_unlock(&c->current_job_lock);
  85 }
  86
  87 void avcodec_thread_free(AVCodecContext *avctx)
  88 {
  89     ThreadContext *c = avctx->thread_opaque;
  90     int i;
  91
  92     pthread_mutex_lock(&c->current_job_lock);
  93     c->done = 1;
  94     pthread_cond_broadcast(&c->current_job_cond);
  95     pthread_mutex_unlock(&c->current_job_lock);
  96
  97     for (i=0; i<avctx->thread_count; i++)
  98          pthread_join(c->workers[i], NULL);
  99
 100     pthread_mutex_destroy(&c->current_job_lock);
 101     pthread_cond_destroy(&c->current_job_cond);
 102     pthread_cond_destroy(&c->last_job_cond);
 103     av_free(c->workers);
 104     av_freep(&avctx->thread_opaque);
 105 }
 106
 107 int avcodec_thread_execute(AVCodecContext *avctx, action_func* func, void *arg, int *ret, int job_count, int job_size)
 108 {
 109     ThreadContext *c= avctx->thread_opaque;
 110     int dummy_ret;
 111
 112     if (job_count <= 0)
 113         return 0;
 114
 115     pthread_mutex_lock(&c->current_job_lock);
 116
 117     c->current_job = avctx->thread_count;
 118     c->job_count = job_count;
 119     c->job_size = job_size;
 120     c->args = arg;
 121     c->func = func;
 122     if (ret) {
 123         c->rets = ret;
 124         c->rets_count = job_count;
 125     } else {
 126         c->rets = &dummy_ret;
 127         c->rets_count = 1;
 128     }
 129     pthread_cond_broadcast(&c->current_job_cond);
 130
 131     avcodec_thread_park_workers(c, avctx->thread_count);
 132
 133     return 0;
 134 }
 135
 136 int avcodec_thread_execute2(AVCodecContext *avctx, action_func2* func2, void *arg, int *ret, int job_count)
 137 {
 138     ThreadContext *c= avctx->thread_opaque;
 139     c->func2 = func2;
 140     return avcodec_thread_execute(avctx, NULL, arg, ret, job_count, 0);
 141 }
 142
 143 int avcodec_thread_init(AVCodecContext *avctx, int thread_count)
 144 {
 145     int i;
 146     ThreadContext *c;
 147
 148     c = av_mallocz(sizeof(ThreadContext));
 149     if (!c)
 150         return -1;
 151
 152     c->workers = av_mallocz(sizeof(pthread_t)*thread_count);
 153     if (!c->workers) {
 154         av_free(c);
 155         return -1;
 156     }
 157
 158     avctx->thread_opaque = c;
 159     avctx->thread_count = thread_count;
 160     c->current_job = 0;
 161     c->job_count = 0;
 162     c->job_size = 0;
 163     c->done = 0;
 164     pthread_cond_init(&c->current_job_cond, NULL);
 165     pthread_cond_init(&c->last_job_cond, NULL);
 166     pthread_mutex_init(&c->current_job_lock, NULL);
 167     pthread_mutex_lock(&c->current_job_lock);
 168     for (i=0; i<thread_count; i++) {
 169         if(pthread_create(&c->workers[i], NULL, worker, avctx)) {
 170            avctx->thread_count = i;
 171            pthread_mutex_unlock(&c->current_job_lock);
 172            avcodec_thread_free(avctx);
 173            return -1;
 174         }
 175     }
 176
 177     avcodec_thread_park_workers(c, thread_count);
 178
 179     avctx->execute = avcodec_thread_execute;
 180     avctx->execute2 = avcodec_thread_execute2;
 181     return 0;
 182 }