[FFmpeg-devel] [PATCH 01/14] vvcdec: add thread executor
Rémi Denis-Courmont
remi at remlab.net
Sun May 21 16:15:12 EEST 2023
Le sunnuntaina 21. toukokuuta 2023, 16.03.06 EEST Nuo Mi a écrit :
> The executor design pattern was inroduced by java
> <https://docs.oracle.com/en/java/javase/20/docs/api/java.base/java/util/conc
> urrent/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. ---
> libavcodec/Makefile | 1 +
> libavcodec/vvc/Makefile | 4 +
> libavcodec/vvc/vvc_executor.c | 193 ++++++++++++++++++++++++++++++++++
> libavcodec/vvc/vvc_executor.h | 73 +++++++++++++
> 4 files changed, 271 insertions(+)
> create mode 100644 libavcodec/vvc/Makefile
> create mode 100644 libavcodec/vvc/vvc_executor.c
> create mode 100644 libavcodec/vvc/vvc_executor.h
>
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index dab09f483a..b1fcbf71b2 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -62,6 +62,7 @@ OBJS = ac3_parser.o
> \ xiph.o
> \
>
> # subsystems
> +include $(SRC_PATH)/libavcodec/vvc/Makefile
> OBJS-$(CONFIG_AANDCTTABLES) += aandcttab.o
> OBJS-$(CONFIG_AC3DSP) += ac3dsp.o ac3.o ac3tab.o
> OBJS-$(CONFIG_ADTS_HEADER) += adts_header.o
> mpeg4audio_sample_rates.o diff --git a/libavcodec/vvc/Makefile
> b/libavcodec/vvc/Makefile
> new file mode 100644
> index 0000000000..c4b93e0389
> --- /dev/null
> +++ b/libavcodec/vvc/Makefile
> @@ -0,0 +1,4 @@
> +clean::
> + $(RM) $(CLEANSUFFIXES:%=libavcodec/vvc/%)
> +
> +OBJS-$(CONFIG_VVC_DECODER) += vvc/vvc_executor.o
> diff --git a/libavcodec/vvc/vvc_executor.c b/libavcodec/vvc/vvc_executor.c
> new file mode 100644
> index 0000000000..f2afdf79ae
> --- /dev/null
> +++ b/libavcodec/vvc/vvc_executor.c
> @@ -0,0 +1,193 @@
> +/*
> + * VVC video Decoder
> + *
> + * Copyright (C) 2022 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 "libavutil/avutil.h"
> +#include "libavutil/thread.h"
> +
> +#include "vvc_executor.h"
This does not seem specific to VVC in any way, so the naming (and choice of
folder placement) is rather weird.
> +
> +typedef struct ThreadInfo {
> + int idx;
> + VVCExecutor *e;
> + pthread_t thread;
> +} ThreadInfo;
> +
> +struct VVCExecutor {
> + VVCTaskCallbacks cb;
> + ThreadInfo *threads;
> + uint8_t *local_contexts;
It seems odd and needless complex to separate this from the thread info. It
looks like you could simply append a pointer or a flexible array to ThreadInfo
instead.
> + int thread_count;
> +
> + pthread_mutex_t lock;
> + pthread_cond_t cond;
> + int die;
> + VVCTasklet *tasks;
> +};
> +
> +static void remove_task(VVCTasklet **prev, VVCTasklet *t)
> +{
> + *prev = t->next;
> + t->next = NULL;
> +}
> +
> +static void add_task(VVCTasklet **prev, VVCTasklet *t)
> +{
> + t->next = *prev;
> + *prev = t;
> +}
> +
> +static void *executor_worker_task(void *data)
> +{
> + ThreadInfo *ti = (ThreadInfo*)data;
> + VVCExecutor *e = ti->e;
> + void *lc = e->local_contexts + ti->idx *
> e->cb.local_context_size;
> + VVCTasklet **prev;
> + VVCTaskCallbacks *cb = &e->cb;
> +
> + pthread_mutex_lock(&e->lock);
> + while (1) {
> + VVCTasklet* t = NULL;
> + if (e->die) break;
> +
> + for (prev = &e->tasks; *prev; prev = &(*prev)->next) {
> + if (cb->ready(*prev, cb->user_data)) {
> + t = *prev;
> + break;
> + }
> + }
> + if (t) {
> + //found one task
> + remove_task(prev, t);
> + pthread_mutex_unlock(&e->lock);
> + cb->run(t, lc, cb->user_data);
> + pthread_mutex_lock(&e->lock);
> + } else {
> + //no task in one loop
> + pthread_cond_wait(&e->cond, &e->lock);
> + }
> + }
> + pthread_mutex_unlock(&e->lock);
> + return NULL;
> +}
> +
> +VVCExecutor* ff_vvc_executor_alloc(const VVCTaskCallbacks *cb, int
> thread_count) +{
> + VVCExecutor *e;
> + int i, j, ret;
> + 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_malloc(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_contexts;
> + for (i = 0; i < thread_count; i++) {
> + ThreadInfo *ti = e->threads + i;
> + ti->e = e;
> + ti->idx = i;
> + }
> +
> + ret = pthread_mutex_init(&e->lock, NULL);
> + if (ret)
> + goto free_threads;
> +
> + ret = pthread_cond_init(&e->cond, NULL);
> + if (ret)
> + goto destroy_lock;
> +
> + for (i = 0; i < thread_count; i++) {
> + ThreadInfo *ti = e->threads + i;
> + ret = pthread_create(&ti->thread, NULL, executor_worker_task, ti);
> + if (ret)
> + goto join_threads;
> + }
> + e->thread_count = thread_count;
> + return e;
> +
> +join_threads:
> + pthread_mutex_lock(&e->lock);
> + e->die = 1;
> + pthread_cond_broadcast(&e->cond);
> + pthread_mutex_unlock(&e->lock);
> + for (j = 0; j < i; j++)
> + pthread_join(e->threads[j].thread, NULL);
> + pthread_cond_destroy(&e->cond);
> +destroy_lock:
> + pthread_mutex_destroy(&e->lock);
> +free_threads:
> + av_free(e->threads);
> +free_contexts:
> + av_free(e->local_contexts);
> +free_executor:
> + free(e);
> + return NULL;
> +}
> +
> +void ff_vvc_executor_free(VVCExecutor **executor)
> +{
> + VVCExecutor *e;
> + if (!executor || !*executor)
> + return;
> + e = *executor;
> +
> + //singal 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);
> + pthread_cond_destroy(&e->cond);
> + pthread_mutex_destroy(&e->lock);
> +
> + av_free(e->threads);
> + av_free(e->local_contexts);
> +
> + av_freep(executor);
> +}
> +
> +void ff_vvc_executor_execute(VVCExecutor *e, VVCTasklet *t)
> +{
> + VVCTaskCallbacks *cb = &e->cb;
> + VVCTasklet **prev;
> +
> + pthread_mutex_lock(&e->lock);
> + 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);
> +}
> +
> +void ff_vvc_executor_wakeup(VVCExecutor *e)
> +{
> + pthread_mutex_lock(&e->lock);
> + pthread_cond_broadcast(&e->cond);
> + pthread_mutex_unlock(&e->lock);
Signaling a condition variable without changing any state makes no sense.
> +}
--
Rémi Denis-Courmont
http://www.remlab.net/
More information about the ffmpeg-devel
mailing list