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 #include "common.h"
  29
  30 typedef int (action_t)(AVCodecContext *c, void *arg);
  31
  32 typedef struct ThreadContext {
  33     pthread_t *workers;
  34     action_t *func;
  35     void **args;
  36     int *rets;
  37     int rets_count;
  38     int job_count;
  39
  40     pthread_cond_t last_job_cond;
  41     pthread_cond_t current_job_cond;
  42     pthread_mutex_t current_job_lock;
  43     int current_job;
  44     int done;
  45 } ThreadContext;
  46
  47 static void* worker(void *v)
  48 {
  49     AVCodecContext *avctx = v;
  50     ThreadContext *c = avctx->thread_opaque;
  51     int our_job = c->job_count;
  52     int thread_count = avctx->thread_count;
  53     int self_id;
  54
  55     pthread_mutex_lock(&c->current_job_lock);
  56     self_id = c->current_job++;
  57     for (;;){
  58         while (our_job >= c->job_count) {
  59             if (c->current_job == thread_count + c->job_count)
  60                 pthread_cond_signal(&c->last_job_cond);
  61
  62             pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
  63             our_job = self_id;
  64
  65             if (c->done) {
  66                 pthread_mutex_unlock(&c->current_job_lock);
  67                 return NULL;
  68             }
  69         }
  70         pthread_mutex_unlock(&c->current_job_lock);
  71
  72         c->rets[our_job%c->rets_count] = c->func(avctx, c->args[our_job]);
  73
  74         pthread_mutex_lock(&c->current_job_lock);
  75         our_job = c->current_job++;
  76     }
  77 }
  78
  79 static av_always_inline void avcodec_thread_park_workers(ThreadContext *c, int thread_count)
  80 {
  81     pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
  82     pthread_mutex_unlock(&c->current_job_lock);
  83 }
  84
  85 void avcodec_thread_free(AVCodecContext *avctx)
  86 {
  87     ThreadContext *c = avctx->thread_opaque;
  88     int i;
  89
  90     pthread_mutex_lock(&c->current_job_lock);
  91     c->done = 1;
  92     pthread_cond_broadcast(&c->current_job_cond);
  93     pthread_mutex_unlock(&c->current_job_lock);
  94
  95     for (i=0; i<avctx->thread_count; i++)
  96          pthread_join(c->workers[i], NULL);
  97
  98     pthread_mutex_destroy(&c->current_job_lock);
  99     pthread_cond_destroy(&c->current_job_cond);
 100     pthread_cond_destroy(&c->last_job_cond);
 101     av_free(c->workers);
 102     av_free(c);
 103 }
 104
 105 int avcodec_thread_execute(AVCodecContext *avctx, action_t* func, void **arg, int *ret, int job_count)
 106 {
 107     ThreadContext *c= avctx->thread_opaque;
 108     int dummy_ret;
 109
 110     if (job_count <= 0)
 111         return 0;
 112
 113     pthread_mutex_lock(&c->current_job_lock);
 114
 115     c->current_job = avctx->thread_count;
 116     c->job_count = job_count;
 117     c->args = arg;
 118     c->func = func;
 119     if (ret) {
 120         c->rets = ret;
 121         c->rets_count = job_count;
 122     } else {
 123         c->rets = &dummy_ret;
 124         c->rets_count = 1;
 125     }
 126     pthread_cond_broadcast(&c->current_job_cond);
 127
 128     avcodec_thread_park_workers(c, avctx->thread_count);
 129
 130     return 0;
 131 }
 132
 133 int avcodec_thread_init(AVCodecContext *avctx, int thread_count)
 134 {
 135     int i;
 136     ThreadContext *c;
 137
 138     c = av_mallocz(sizeof(ThreadContext));
 139     if (!c)
 140         return -1;
 141
 142     c->workers = av_mallocz(sizeof(pthread_t)*thread_count);
 143     if (!c->workers) {
 144         av_free(c);
 145         return -1;
 146     }
 147
 148     avctx->thread_opaque = c;
 149     avctx->thread_count = thread_count;
 150     c->current_job = 0;
 151     c->job_count = 0;
 152     c->done = 0;
 153     pthread_cond_init(&c->current_job_cond, NULL);
 154     pthread_cond_init(&c->last_job_cond, NULL);
 155     pthread_mutex_init(&c->current_job_lock, NULL);
 156     pthread_mutex_lock(&c->current_job_lock);
 157     for (i=0; i<thread_count; i++) {
 158         if(pthread_create(&c->workers[i], NULL, worker, avctx)) {
 159            avctx->thread_count = i;
 160            pthread_mutex_unlock(&c->current_job_lock);
 161            avcodec_thread_free(avctx);
 162            return -1;
 163         }
 164     }
 165
 166     avcodec_thread_park_workers(c, thread_count);
 167
 168     avctx->execute = avcodec_thread_execute;
 169     return 0;
 170 }