/* * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Libavfilter multithreading support */ #include "config.h" #include "libavutil/common.h"#include "libavutil/cpu.h"#include "libavutil/mem.h" #include "avfilter.h"#include "internal.h"#include "thread.h" #if HAVE_PTHREADS#include <pthread.h>#elif HAVE_W32THREADS#include "compat/w32pthreads.h"#endif typedef struct ThreadContext {    AVFilterGraph *graph;     int nb_threads;    pthread_t *workers;    action_func *func;     /* per-execute perameters */    AVFilterContext *ctx;    void *arg;    int   *rets;    int nb_rets;    int nb_jobs;     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* attribute_align_arg worker(void *v){    ThreadContext *c = v;    int our_job      = c->nb_jobs;    int nb_threads   = c->nb_threads;    int self_id;     pthread_mutex_lock(&c->current_job_lock);    self_id = c->current_job++;    for (;;) {        while (our_job >= c->nb_jobs) {            if (c->current_job == nb_threads + c->nb_jobs)                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->nb_rets] = c->func(c->ctx, c->arg, our_job, c->nb_jobs);         pthread_mutex_lock(&c->current_job_lock);        our_job = c->current_job++;    }} static void slice_thread_uninit(ThreadContext *c){    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 < c->nb_threads; 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_freep(&c->workers);} static void slice_thread_park_workers(ThreadContext *c){    pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);    pthread_mutex_unlock(&c->current_job_lock);} static int thread_execute(AVFilterContext *ctx, action_func *func,                          void *arg, int *ret, int nb_jobs){    ThreadContext *c = ctx->graph->internal->thread;    int dummy_ret;     if (nb_jobs <= 0)        return 0;     pthread_mutex_lock(&c->current_job_lock);     c->current_job = c->nb_threads;    c->nb_jobs     = nb_jobs;    c->ctx         = ctx;    c->arg         = arg;    c->func        = func;    if (ret) {        c->rets    = ret;        c->nb_rets = nb_jobs;    } else {        c->rets    = &dummy_ret;        c->nb_rets = 1;    }    pthread_cond_broadcast(&c->current_job_cond);     slice_thread_park_workers(c);     return 0;} static int thread_init_internal(ThreadContext *c, int nb_threads){    int i, ret;     if (!nb_threads) {        int nb_cpus = av_cpu_count();        av_log(c->graph, AV_LOG_DEBUG, "Detected %d logical cores.\n", nb_cpus);        // use number of cores + 1 as thread count if there is more than one        if (nb_cpus > 1)            nb_threads = nb_cpus + 1;        else            nb_threads = 1;    }     if (nb_threads <= 1)        return 1;     c->nb_threads = nb_threads;    c->workers = av_mallocz(sizeof(*c->workers) * nb_threads);    if (!c->workers)        return AVERROR(ENOMEM);     c->current_job = 0;    c->nb_jobs     = 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 < nb_threads; i++) {        ret = pthread_create(&c->workers[i], NULL, worker, c);        if (ret) {           pthread_mutex_unlock(&c->current_job_lock);           c->nb_threads = i;           slice_thread_uninit(c);           return AVERROR(ret);        }    }     slice_thread_park_workers(c);     return c->nb_threads;} int ff_graph_thread_init(AVFilterGraph *graph){    int ret; #if HAVE_W32THREADS    w32thread_init();#endif     if (graph->nb_threads == 1) {        graph->thread_type = 0;        return 0;    }     graph->internal->thread = av_mallocz(sizeof(ThreadContext));    if (!graph->internal->thread)        return AVERROR(ENOMEM);     ret = thread_init_internal(graph->internal->thread, graph->nb_threads);    if (ret <= 1) {        av_freep(&graph->internal->thread);        graph->thread_type = 0;        graph->nb_threads  = 1;        return (ret < 0) ? ret : 0;    }    graph->nb_threads = ret;     graph->internal->thread_execute = thread_execute;     return 0;} void ff_graph_thread_free(AVFilterGraph *graph){    if (graph->internal->thread)        slice_thread_uninit(graph->internal->thread);    av_freep(&graph->internal->thread);}