mirror of
https://git.videolan.org/git/ffmpeg.git
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![Clément Bœsch](/assets/img/avatar_default.png)
If ret is NULL, a dummy common holder is created to hold *all* the parallel function returns, which gets written concurrently. This commit simplify the whole logic by simply not writing to that holder when not set.
225 lines
5.7 KiB
C
225 lines
5.7 KiB
C
/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Libavfilter multithreading support
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*/
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#include "config.h"
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#include "libavutil/common.h"
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#include "libavutil/cpu.h"
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#include "libavutil/mem.h"
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#include "libavutil/thread.h"
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#include "avfilter.h"
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#include "internal.h"
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#include "thread.h"
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typedef struct ThreadContext {
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AVFilterGraph *graph;
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int nb_threads;
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pthread_t *workers;
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avfilter_action_func *func;
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/* per-execute parameters */
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AVFilterContext *ctx;
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void *arg;
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int *rets;
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int nb_jobs;
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pthread_cond_t last_job_cond;
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pthread_cond_t current_job_cond;
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pthread_mutex_t current_job_lock;
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int current_job;
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unsigned int current_execute;
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int done;
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} ThreadContext;
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static void* attribute_align_arg worker(void *v)
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{
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ThreadContext *c = v;
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int our_job = c->nb_jobs;
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int nb_threads = c->nb_threads;
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unsigned int last_execute = 0;
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int ret, self_id;
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pthread_mutex_lock(&c->current_job_lock);
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self_id = c->current_job++;
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for (;;) {
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while (our_job >= c->nb_jobs) {
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if (c->current_job == nb_threads + c->nb_jobs)
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pthread_cond_signal(&c->last_job_cond);
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while (last_execute == c->current_execute && !c->done)
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pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
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last_execute = c->current_execute;
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our_job = self_id;
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if (c->done) {
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pthread_mutex_unlock(&c->current_job_lock);
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return NULL;
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}
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}
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pthread_mutex_unlock(&c->current_job_lock);
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ret = c->func(c->ctx, c->arg, our_job, c->nb_jobs);
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if (c->rets)
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c->rets[our_job % c->nb_jobs] = ret;
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pthread_mutex_lock(&c->current_job_lock);
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our_job = c->current_job++;
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}
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}
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static void slice_thread_uninit(ThreadContext *c)
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{
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int i;
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pthread_mutex_lock(&c->current_job_lock);
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c->done = 1;
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pthread_cond_broadcast(&c->current_job_cond);
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pthread_mutex_unlock(&c->current_job_lock);
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for (i = 0; i < c->nb_threads; i++)
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pthread_join(c->workers[i], NULL);
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pthread_mutex_destroy(&c->current_job_lock);
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pthread_cond_destroy(&c->current_job_cond);
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pthread_cond_destroy(&c->last_job_cond);
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av_freep(&c->workers);
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}
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static void slice_thread_park_workers(ThreadContext *c)
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{
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while (c->current_job != c->nb_threads + c->nb_jobs)
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pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
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pthread_mutex_unlock(&c->current_job_lock);
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}
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static int thread_execute(AVFilterContext *ctx, avfilter_action_func *func,
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void *arg, int *ret, int nb_jobs)
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{
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ThreadContext *c = ctx->graph->internal->thread;
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if (nb_jobs <= 0)
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return 0;
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pthread_mutex_lock(&c->current_job_lock);
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c->current_job = c->nb_threads;
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c->nb_jobs = nb_jobs;
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c->ctx = ctx;
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c->arg = arg;
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c->func = func;
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c->rets = ret;
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c->current_execute++;
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pthread_cond_broadcast(&c->current_job_cond);
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slice_thread_park_workers(c);
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return 0;
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}
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static int thread_init_internal(ThreadContext *c, int nb_threads)
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{
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int i, ret;
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if (!nb_threads) {
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int nb_cpus = av_cpu_count();
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// use number of cores + 1 as thread count if there is more than one
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if (nb_cpus > 1)
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nb_threads = nb_cpus + 1;
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else
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nb_threads = 1;
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}
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if (nb_threads <= 1)
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return 1;
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c->nb_threads = nb_threads;
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c->workers = av_mallocz_array(sizeof(*c->workers), nb_threads);
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if (!c->workers)
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return AVERROR(ENOMEM);
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c->current_job = 0;
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c->nb_jobs = 0;
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c->done = 0;
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pthread_cond_init(&c->current_job_cond, NULL);
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pthread_cond_init(&c->last_job_cond, NULL);
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pthread_mutex_init(&c->current_job_lock, NULL);
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pthread_mutex_lock(&c->current_job_lock);
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for (i = 0; i < nb_threads; i++) {
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ret = pthread_create(&c->workers[i], NULL, worker, c);
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if (ret) {
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pthread_mutex_unlock(&c->current_job_lock);
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c->nb_threads = i;
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slice_thread_uninit(c);
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return AVERROR(ret);
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}
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}
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slice_thread_park_workers(c);
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return c->nb_threads;
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}
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int ff_graph_thread_init(AVFilterGraph *graph)
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{
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int ret;
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#if HAVE_W32THREADS
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w32thread_init();
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#endif
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if (graph->nb_threads == 1) {
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graph->thread_type = 0;
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return 0;
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}
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graph->internal->thread = av_mallocz(sizeof(ThreadContext));
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if (!graph->internal->thread)
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return AVERROR(ENOMEM);
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ret = thread_init_internal(graph->internal->thread, graph->nb_threads);
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if (ret <= 1) {
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av_freep(&graph->internal->thread);
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graph->thread_type = 0;
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graph->nb_threads = 1;
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return (ret < 0) ? ret : 0;
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}
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graph->nb_threads = ret;
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graph->internal->thread_execute = thread_execute;
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return 0;
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}
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void ff_graph_thread_free(AVFilterGraph *graph)
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{
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if (graph->internal->thread)
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slice_thread_uninit(graph->internal->thread);
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av_freep(&graph->internal->thread);
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}
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