On Wed, Jul 19, 2023 at 9:13 PM Nuo Mi <nuomi2...@gmail.com> wrote:
> The executor design pattern was inroduced by java > < > https://docs.oracle.com/en/java/javase/20/docs/api/java.base/java/util/concurrent/Executor.html > > > it also adapted by python > <https://docs.python.org/3/library/concurrent.futures.html> > Compared to handcrafted thread pool management, it greatly simplifies the > thread code. > --- > libavutil/Makefile | 2 + > libavutil/executor.c | 201 +++++++++++++++++++++++++++++++++++++++++++ > libavutil/executor.h | 67 +++++++++++++++ > 3 files changed, 270 insertions(+) > create mode 100644 libavutil/executor.c > create mode 100644 libavutil/executor.h > > diff --git a/libavutil/Makefile b/libavutil/Makefile > index bd9c6f9e32..b40aacdd06 100644 > --- a/libavutil/Makefile > +++ b/libavutil/Makefile > @@ -31,6 +31,7 @@ HEADERS = adler32.h > \ > encryption_info.h \ > error.h \ > eval.h \ > + executor.h \ > fifo.h \ > file.h \ > frame.h \ > @@ -126,6 +127,7 @@ OBJS = adler32.o > \ > encryption_info.o \ > error.o \ > eval.o \ > + executor.o \ > fifo.o \ > file.o \ > file_open.o \ > diff --git a/libavutil/executor.c b/libavutil/executor.c > new file mode 100644 > index 0000000000..9823fc3d5d > --- /dev/null > +++ b/libavutil/executor.c > @@ -0,0 +1,201 @@ > +/* > + * Copyright (C) 2023 Nuo Mi > + * > + * 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 "internal.h" > +#include "mem.h" > +#include "thread.h" > + > +#include "executor.h" > + > +#if !HAVE_THREADS > +#define pthread_create(t, a, s, ar) 0 > +#define pthread_join(t, r) do {} while(0) > + > +#define pthread_cond_init(c, a) 0 > +#define pthread_cond_broadcast(c) do {} while(0) > +#define pthread_cond_signal(c) do {} while(0) > +#define pthread_cond_wait(c, m) do {} while(0) > +#define pthread_cond_destroy(c) do {} while(0) > + > +#define pthread_mutex_init(m, a) 0 > +#define pthread_mutex_lock(l) do {} while(0) > +#define pthread_mutex_unlock(l) do {} while(0) > +#define pthread_mutex_destroy(l) do {} while(0) > +#endif > + > +typedef struct ThreadInfo { > + AVExecutor *e; > + pthread_t thread; > +} ThreadInfo; > + > +struct AVExecutor { > + AVTaskCallbacks cb; > + int thread_count; > + > + ThreadInfo *threads; > + uint8_t *local_contexts; > + > + pthread_mutex_t lock; > + pthread_cond_t cond; > + int die; > + > + AVTask *tasks; > +}; > + > +static AVTask* remove_task(AVTask **prev, AVTask *t) > +{ > + *prev = t->next; > + t->next = NULL; > + return t; > +} > + > +static void add_task(AVTask **prev, AVTask *t) > +{ > + t->next = *prev; > + *prev = t; > +} > + > +static int run_one_task(AVExecutor *e, void *lc) > +{ > + AVTaskCallbacks *cb = &e->cb; > + AVTask **prev; > + > + for (prev = &e->tasks; *prev && !cb->ready(*prev, cb->user_data); > prev = &(*prev)->next) > + /* nothing */; > + if (*prev) { > + AVTask *t = remove_task(prev, *prev); > + pthread_mutex_unlock(&e->lock); > + cb->run(t, lc, cb->user_data); > + pthread_mutex_lock(&e->lock); > + return 1; > + } > + return 0; > +} > + > +#if HAVE_THREADS > +static void *executor_worker_task(void *data) > +{ > + ThreadInfo *ti = (ThreadInfo*)data; > + AVExecutor *e = ti->e; > + void *lc = e->local_contexts + (ti - e->threads) * > e->cb.local_context_size; > + > + pthread_mutex_lock(&e->lock); > + while (1) { > + if (e->die) break; > + > + if (!run_one_task(e, lc)) { > + //no task in one loop > + pthread_cond_wait(&e->cond, &e->lock); > + } > + } > + pthread_mutex_unlock(&e->lock); > + return NULL; > +} > +#endif > + > +static void executor_free(AVExecutor *e, const int has_lock, const int > has_cond) > +{ > + if (e->thread_count) { > + //signal die > + pthread_mutex_lock(&e->lock); > + e->die = 1; > + pthread_cond_broadcast(&e->cond); > + pthread_mutex_unlock(&e->lock); > + > + for (int i = 0; i < e->thread_count; i++) > + pthread_join(e->threads[i].thread, NULL); > + } > + if (has_cond) > + pthread_cond_destroy(&e->cond); > + if (has_lock) > + pthread_mutex_destroy(&e->lock); > + > + av_free(e->threads); > + av_free(e->local_contexts); > + > + av_free(e); > +} > + > +AVExecutor* avpriv_executor_alloc(const AVTaskCallbacks *cb, int > thread_count) > +{ > + AVExecutor *e; > + int has_lock = 0, has_cond = 0; > + if (!cb || !cb->user_data || !cb->ready || !cb->run || > !cb->priority_higher) > + return NULL; > + > + e = av_calloc(1, sizeof(*e)); > + if (!e) > + return NULL; > + e->cb = *cb; > + > + e->local_contexts = av_calloc(thread_count, e->cb.local_context_size); > + if (!e->local_contexts) > + goto free_executor; > + > + e->threads = av_calloc(thread_count, sizeof(*e->threads)); > + if (!e->threads) > + goto free_executor; > + > + has_lock = !pthread_mutex_init(&e->lock, NULL); > + has_cond = !pthread_cond_init(&e->cond, NULL); > + > + if (!has_lock || !has_cond) > + goto free_executor; > + > + for (/* nothing */; e->thread_count < thread_count; > e->thread_count++) { > + ThreadInfo *ti = e->threads + e->thread_count; > + ti->e = e; > + if (pthread_create(&ti->thread, NULL, executor_worker_task, ti)) > + goto free_executor; > + } > + return e; > + > +free_executor: > + executor_free(e, has_lock, has_cond); > + return NULL; > +} > + > +void avpriv_executor_free(AVExecutor **executor) > +{ > + if (!executor || !*executor) > + return; > + executor_free(*executor, 1, 1); > + *executor = NULL; > +} > + > +void avpriv_executor_execute(AVExecutor *e, AVTask *t) > +{ > + AVTaskCallbacks *cb = &e->cb; > + AVTask **prev; > + > + pthread_mutex_lock(&e->lock); > + if (t) { > + for (prev = &e->tasks; *prev && cb->priority_higher(*prev, t); > prev = &(*prev)->next) > + /* nothing */; > + add_task(prev, t); > + } > + pthread_cond_signal(&e->cond); > + pthread_mutex_unlock(&e->lock); > + > +#if !HAVE_THREADS > + // We are running in a single-threaded environment, so we must handle > all tasks ourselves > + while (run_one_task(e, e->local_contexts)) > + /* nothing */; > +#endif > +} > diff --git a/libavutil/executor.h b/libavutil/executor.h > new file mode 100644 > index 0000000000..48c7d47c7d > --- /dev/null > +++ b/libavutil/executor.h > @@ -0,0 +1,67 @@ > +/* > + * Copyright (C) 2023 Nuo Mi > + * > + * 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 > + */ > + > +#ifndef AVUTIL_EXECUTOR_H > +#define AVUTIL_EXECUTOR_H > + > +typedef struct AVExecutor AVExecutor; > +typedef struct AVTask AVTask; > + > +struct AVTask { > + AVTask *next; > +}; > + > +typedef struct AVTaskCallbacks { > + void *user_data; > + > + int local_context_size; > + > + // return 1 if a's priority > b's priority > + int (*priority_higher)(const AVTask *a, const AVTask *b); > + > + // task is ready for run > + int (*ready)(const AVTask *t, void *user_data); > + > + // run the task > + int (*run)(AVTask *t, void *local_context, void *user_data); > +} AVTaskCallbacks; > + > +/** > + * Alloc executor > + * @param callbacks callback strucutre for executor > + * @param thread_count worker thread number > + * @return return the executor > + */ > +AVExecutor* avpriv_executor_alloc(const AVTaskCallbacks *callbacks, int > thread_count); > + > +/** > + * Free executor > + * @param e pointer to executor > + */ > +void avpriv_executor_free(AVExecutor **e); > + > +/** > + * Add task to executor > + * @param e pointer to executor > + * @param t pointer to task. If NULL, it will wakeup one work thread > + */ > +void avpriv_executor_execute(AVExecutor *e, AVTask *t); > + > +#endif //AVUTIL_EXECUTOR_H > -- > 2.25.1 > > Changes since v2: * move executor to avutil * fix for --disable-pthreads * remove duplicate free code in executor_alloc and executor_free I also disabled the HAVE_THREADS macro in this file only for testing purposes. The executor is also functional in single-threaded environments. _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
