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