[FFmpeg-devel] [PATCH v2 01/14] vvcdec: add thread executor
Nuo Mi
nuomi2021 at gmail.com
Fri Jul 7 17:05:27 EEST 2023
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.
---
libavcodec/Makefile | 1 +
libavcodec/executor.c | 182 ++++++++++++++++++++++++++++++++++++++++
libavcodec/executor.h | 67 +++++++++++++++
libavcodec/vvc/Makefile | 4 +
4 files changed, 254 insertions(+)
create mode 100644 libavcodec/executor.c
create mode 100644 libavcodec/executor.h
create mode 100644 libavcodec/vvc/Makefile
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 1b0226c089..4a3c7a7a1f 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/executor.c b/libavcodec/executor.c
new file mode 100644
index 0000000000..c5094f608a
--- /dev/null
+++ b/libavcodec/executor.c
@@ -0,0 +1,182 @@
+/*
+ * 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 "executor.h"
+
+typedef struct ThreadInfo {
+ Executor *e;
+ pthread_t thread;
+} ThreadInfo;
+
+struct Executor {
+ TaskletCallbacks cb;
+ ThreadInfo *threads;
+ uint8_t *local_contexts;
+ int thread_count;
+
+ pthread_mutex_t lock;
+ pthread_cond_t cond;
+ int die;
+ Tasklet *tasks;
+};
+
+static void remove_task(Tasklet **prev, Tasklet *t)
+{
+ *prev = t->next;
+ t->next = NULL;
+}
+
+static void add_task(Tasklet **prev, Tasklet *t)
+{
+ t->next = *prev;
+ *prev = t;
+}
+
+static void *executor_worker_task(void *data)
+{
+ ThreadInfo *ti = (ThreadInfo*)data;
+ Executor *e = ti->e;
+ void *lc = e->local_contexts + (ti - e->threads) * e->cb.local_context_size;
+ Tasklet **prev;
+ TaskletCallbacks *cb = &e->cb;
+
+ pthread_mutex_lock(&e->lock);
+ while (1) {
+ Tasklet* 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;
+}
+
+Executor* ff_executor_alloc(const TaskletCallbacks *cb, int thread_count)
+{
+ Executor *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_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_contexts;
+ 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;
+ ti->e = e;
+ 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_executor_free(Executor **executor)
+{
+ Executor *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_executor_execute(Executor *e, Tasklet *t)
+{
+ TaskletCallbacks *cb = &e->cb;
+ Tasklet **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);
+}
\ No newline at end of file
diff --git a/libavcodec/executor.h b/libavcodec/executor.h
new file mode 100644
index 0000000000..4b641acce6
--- /dev/null
+++ b/libavcodec/executor.h
@@ -0,0 +1,67 @@
+/*
+ * 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
+ */
+
+#ifndef AVCODEC_EXECUTOR_H
+#define AVCODEC_EXECUTOR_H
+
+typedef struct Executor Executor;
+typedef struct Tasklet Tasklet;
+
+struct Tasklet {
+ Tasklet *next;
+};
+
+typedef struct TaskletCallbacks {
+ void *user_data;
+
+ int local_context_size;
+
+ // return 1 if a's priority > b's priority
+ int (*priority_higher)(const Tasklet *a, const Tasklet *b);
+
+ // task is ready for run
+ int (*ready)(const Tasklet *t, void *user_data);
+
+ // run the task
+ int (*run)(Tasklet *t, void *local_context, void *user_data);
+} TaskletCallbacks;
+
+/**
+ * Alloc executor
+ * @param callbacks callback strucutre for executor
+ * @param thread_count worker thread number
+ * @return return the executor
+ */
+Executor* ff_executor_alloc(const TaskletCallbacks *callbacks, int thread_count);
+
+/**
+ * Free executor
+ * @param e pointer to executor
+ */
+void ff_executor_free(Executor **e);
+
+/**
+ * Add task to executor
+ * @param e pointer to executor
+ * @param t pointer to task. If NULL, it will wakeup one work thread
+ */
+void ff_executor_execute(Executor *e, Tasklet *t);
+
+#endif //AVCODEC_EXECUTOR_H
diff --git a/libavcodec/vvc/Makefile b/libavcodec/vvc/Makefile
new file mode 100644
index 0000000000..16cdd04307
--- /dev/null
+++ b/libavcodec/vvc/Makefile
@@ -0,0 +1,4 @@
+clean::
+ $(RM) $(CLEANSUFFIXES:%=libavcodec/vvc/%)
+
+OBJS-$(CONFIG_VVC_DECODER) += executor.o
--
2.25.1
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