ffmpeg/libavcodec/pthread.c

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/*
* Copyright (c) 2004 Roman Shaposhnik.
*
* Many thanks to Steven M. Schultz for providing clever ideas and
* to Michael Niedermayer <michaelni@gmx.at> for writing initial
* implementation.
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <pthread.h>
#include "avcodec.h"
typedef int (action_t)(AVCodecContext *c, void *arg);
typedef struct ThreadContext {
pthread_t *workers;
action_t *func;
void **args;
int *rets;
int rets_count;
int job_count;
pthread_cond_t last_job_cond;
pthread_cond_t current_job_cond;
pthread_mutex_t current_job_lock;
int current_job;
int done;
} ThreadContext;
static void* worker(void *v)
{
AVCodecContext *avctx = v;
ThreadContext *c = avctx->thread_opaque;
int our_job = c->job_count;
int thread_count = avctx->thread_count;
int self_id;
pthread_mutex_lock(&c->current_job_lock);
self_id = c->current_job++;
for (;;){
while (our_job >= c->job_count) {
if (c->current_job == thread_count + c->job_count)
pthread_cond_signal(&c->last_job_cond);
pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
our_job = self_id;
if (c->done) {
pthread_mutex_unlock(&c->current_job_lock);
return NULL;
}
}
pthread_mutex_unlock(&c->current_job_lock);
c->rets[our_job%c->rets_count] = c->func(avctx, c->args[our_job]);
pthread_mutex_lock(&c->current_job_lock);
our_job = c->current_job++;
}
}
static av_always_inline void avcodec_thread_park_workers(ThreadContext *c, int thread_count)
{
pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
pthread_mutex_unlock(&c->current_job_lock);
}
void avcodec_thread_free(AVCodecContext *avctx)
{
ThreadContext *c = avctx->thread_opaque;
int i;
pthread_mutex_lock(&c->current_job_lock);
c->done = 1;
pthread_cond_broadcast(&c->current_job_cond);
pthread_mutex_unlock(&c->current_job_lock);
for (i=0; i<avctx->thread_count; i++)
pthread_join(c->workers[i], NULL);
pthread_mutex_destroy(&c->current_job_lock);
pthread_cond_destroy(&c->current_job_cond);
pthread_cond_destroy(&c->last_job_cond);
av_free(c->workers);
av_freep(&avctx->thread_opaque);
}
int avcodec_thread_execute(AVCodecContext *avctx, action_t* func, void **arg, int *ret, int job_count)
{
ThreadContext *c= avctx->thread_opaque;
int dummy_ret;
if (job_count <= 0)
return 0;
pthread_mutex_lock(&c->current_job_lock);
c->current_job = avctx->thread_count;
c->job_count = job_count;
c->args = arg;
c->func = func;
if (ret) {
c->rets = ret;
c->rets_count = job_count;
} else {
c->rets = &dummy_ret;
c->rets_count = 1;
}
pthread_cond_broadcast(&c->current_job_cond);
avcodec_thread_park_workers(c, avctx->thread_count);
return 0;
}
int avcodec_thread_init(AVCodecContext *avctx, int thread_count)
{
int i;
ThreadContext *c;
c = av_mallocz(sizeof(ThreadContext));
if (!c)
return -1;
c->workers = av_mallocz(sizeof(pthread_t)*thread_count);
if (!c->workers) {
av_free(c);
return -1;
}
avctx->thread_opaque = c;
avctx->thread_count = thread_count;
c->current_job = 0;
c->job_count = 0;
c->done = 0;
pthread_cond_init(&c->current_job_cond, NULL);
pthread_cond_init(&c->last_job_cond, NULL);
pthread_mutex_init(&c->current_job_lock, NULL);
pthread_mutex_lock(&c->current_job_lock);
for (i=0; i<thread_count; i++) {
if(pthread_create(&c->workers[i], NULL, worker, avctx)) {
avctx->thread_count = i;
pthread_mutex_unlock(&c->current_job_lock);
avcodec_thread_free(avctx);
return -1;
}
}
avcodec_thread_park_workers(c, thread_count);
avctx->execute = avcodec_thread_execute;
return 0;
}