git.sesse.net Git - ffmpeg/blob - 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  */
  25 #include <pthread.h>
  26
  27 #include "avcodec.h"
  28
  29 typedef int (action_t)(AVCodecContext *c, void *arg);
  30
  31 typedef struct ThreadContext {
  32     pthread_t *workers;
  33     action_t *func;
  34     void **args;
  35     int *rets;
  36     int rets_count;
  37     int job_count;
  38
  39     pthread_cond_t last_job_cond;
  40     pthread_cond_t current_job_cond;
  41     pthread_mutex_t current_job_lock;
  42     int current_job;
  43     int done;
  44 } ThreadContext;
  45
  46 static void* worker(void *v)
  47 {
  48     AVCodecContext *avctx = v;
  49     ThreadContext *c = avctx->thread_opaque;
  50     int our_job = c->job_count;
  51     int thread_count = avctx->thread_count;
  52     int self_id;
  53
  54     pthread_mutex_lock(&c->current_job_lock);
  55     self_id = c->current_job++;
  56     for (;;){
  57         while (our_job >= c->job_count) {
  58             if (c->current_job == thread_count + c->job_count)
  59                 pthread_cond_signal(&c->last_job_cond);
  60
  61             pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
  62             our_job = self_id;
  63
  64             if (c->done) {
  65                 pthread_mutex_unlock(&c->current_job_lock);
  66                 return NULL;
  67             }
  68         }
  69         pthread_mutex_unlock(&c->current_job_lock);
  70
  71         c->rets[our_job%c->rets_count] = c->func(avctx, c->args[our_job]);
  72
  73         pthread_mutex_lock(&c->current_job_lock);
  74         our_job = c->current_job++;
  75     }
  76 }
  77
  78 static av_always_inline void avcodec_thread_park_workers(ThreadContext *c, int thread_count)
  79 {
  80     pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
  81     pthread_mutex_unlock(&c->current_job_lock);
  82 }
  83
  84 void avcodec_thread_free(AVCodecContext *avctx)
  85 {
  86     ThreadContext *c = avctx->thread_opaque;
  87     int i;
  88
  89     pthread_mutex_lock(&c->current_job_lock);
  90     c->done = 1;
  91     pthread_cond_broadcast(&c->current_job_cond);
  92     pthread_mutex_unlock(&c->current_job_lock);
  93
  94     for (i=0; i<avctx->thread_count; i++)
  95          pthread_join(c->workers[i], NULL);
  96
  97     pthread_mutex_destroy(&c->current_job_lock);
  98     pthread_cond_destroy(&c->current_job_cond);
  99     pthread_cond_destroy(&c->last_job_cond);
 100     av_free(c->workers);
 101     av_free(c);
 102 }
 103
 104 int avcodec_thread_execute(AVCodecContext *avctx, action_t* func, void **arg, int *ret, int job_count)
 105 {
 106     ThreadContext *c= avctx->thread_opaque;
 107     int dummy_ret;
 108
 109     if (job_count <= 0)
 110         return 0;
 111
 112     pthread_mutex_lock(&c->current_job_lock);
 113
 114     c->current_job = avctx->thread_count;
 115     c->job_count = job_count;
 116     c->args = arg;
 117     c->func = func;
 118     if (ret) {
 119         c->rets = ret;
 120         c->rets_count = job_count;
 121     } else {
 122         c->rets = &dummy_ret;
 123         c->rets_count = 1;
 124     }
 125     pthread_cond_broadcast(&c->current_job_cond);
 126
 127     avcodec_thread_park_workers(c, avctx->thread_count);
 128
 129     return 0;
 130 }
 131
 132 int avcodec_thread_init(AVCodecContext *avctx, int thread_count)
 133 {
 134     int i;
 135     ThreadContext *c;
 136
 137     c = av_mallocz(sizeof(ThreadContext));
 138     if (!c)
 139         return -1;
 140
 141     c->workers = av_mallocz(sizeof(pthread_t)*thread_count);
 142     if (!c->workers) {
 143         av_free(c);
 144         return -1;
 145     }
 146
 147     avctx->thread_opaque = c;
 148     avctx->thread_count = thread_count;
 149     c->current_job = 0;
 150     c->job_count = 0;
 151     c->done = 0;
 152     pthread_cond_init(&c->current_job_cond, NULL);
 153     pthread_cond_init(&c->last_job_cond, NULL);
 154     pthread_mutex_init(&c->current_job_lock, NULL);
 155     pthread_mutex_lock(&c->current_job_lock);
 156     for (i=0; i<thread_count; i++) {
 157         if(pthread_create(&c->workers[i], NULL, worker, avctx)) {
 158            avctx->thread_count = i;
 159            pthread_mutex_unlock(&c->current_job_lock);
 160            avcodec_thread_free(avctx);
 161            return -1;
 162         }
 163     }
 164
 165     avcodec_thread_park_workers(c, thread_count);
 166
 167     avctx->execute = avcodec_thread_execute;
 168     return 0;
 169 }