[FFmpeg-devel] [PATCH v3 3/3] avcodec/vvc: simplify priority logical to improve performance for 4K/8K
Nuo Mi
nuomi2021 at gmail.com
Tue Oct 1 16:54:38 EEST 2024
For 4K/8K video processing, it's possible to have over 1,000 tasks pending on the executor.
In such cases, O(n) and O(log(n)) insertion times are too costly.
Reducing this to O(1) will significantly decrease the time spent in critical sections
clip | before | after | delta
------------------------------------------------------------|--------|--------|-------
VVC_HDR_UHDTV2_OpenGOP_7680x4320_50fps_HLG10.bit | 24 | 27 | 12.5%
VVC_HDR_UHDTV2_OpenGOP_7680x4320_50fps_HLG10_HighBitrate.bit| 12 | 17 | 41.7%
tears_of_steel_4k_8M_8bit_2000.vvc | 34 | 102 | 200.0%
VVC_UHDTV1_OpenGOP_3840x2160_60fps_HLG10.bit | 126 | 128 | 1.6%
RitualDance_1920x1080_60_10_420_37_RA.266 | 350 | 378 | 8.0%
NovosobornayaSquare_1920x1080.bin | 341 | 369 | 8.2%
Tango2_3840x2160_60_10_420_27_LD.266 | 69 | 70 | 1.4%
RitualDance_1920x1080_60_10_420_32_LD.266 | 243 | 259 | 6.6%
Chimera_8bit_1080P_1000_frames.vvc | 420 | 392 | -6.7%
BQTerrace_1920x1080_60_10_420_22_RA.vvc | 148 | 144 | -2.7%
---
libavcodec/executor.c | 52 ++++++++++++++++++++++++++---------------
libavcodec/executor.h | 5 ++--
libavcodec/vvc/thread.c | 48 +++++++++++++++----------------------
3 files changed, 55 insertions(+), 50 deletions(-)
diff --git a/libavcodec/executor.c b/libavcodec/executor.c
index 8e6c134ba7..6cea851e6a 100644
--- a/libavcodec/executor.c
+++ b/libavcodec/executor.c
@@ -48,6 +48,11 @@ typedef struct ThreadInfo {
ExecutorThread thread;
} ThreadInfo;
+typedef struct Queue {
+ AVTask *head;
+ AVTask *tail;
+} Queue;
+
struct AVExecutor {
AVTaskCallbacks cb;
int thread_count;
@@ -60,29 +65,39 @@ struct AVExecutor {
AVCond cond;
int die;
- AVTask *tasks;
+ Queue *q;
};
-static AVTask* remove_task(AVTask **prev, AVTask *t)
+static AVTask* remove_task(Queue *q)
{
- *prev = t->next;
- t->next = NULL;
+ AVTask *t = q->head;
+ if (t) {
+ q->head = t->next;
+ t->next = NULL;
+ if (!q->head)
+ q->tail = NULL;
+ }
return t;
}
-static void add_task(AVTask **prev, AVTask *t)
+static void add_task(Queue *q, AVTask *t)
{
- t->next = *prev;
- *prev = t;
+ t->next = NULL;
+ if (!q->head)
+ q->tail = q->head = t;
+ else
+ q->tail = q->tail->next = t;
}
static int run_one_task(AVExecutor *e, void *lc)
{
AVTaskCallbacks *cb = &e->cb;
- AVTask **prev = &e->tasks;
+ AVTask *t = NULL;
+
+ for (int i = 0; i < e->cb.priorities && !t; i++)
+ t = remove_task(e->q + i);
- if (*prev) {
- AVTask *t = remove_task(prev, *prev);
+ if (t) {
if (e->thread_count > 0)
ff_mutex_unlock(&e->lock);
cb->run(t, lc, cb->user_data);
@@ -132,6 +147,7 @@ static void executor_free(AVExecutor *e, const int has_lock, const int has_cond)
ff_mutex_destroy(&e->lock);
av_free(e->threads);
+ av_free(e->q);
av_free(e->local_contexts);
av_free(e);
@@ -141,7 +157,7 @@ AVExecutor* ff_executor_alloc(const AVTaskCallbacks *cb, int thread_count)
{
AVExecutor *e;
int has_lock = 0, has_cond = 0;
- if (!cb || !cb->user_data || !cb->run || !cb->priority_higher)
+ if (!cb || !cb->user_data || !cb->run || !cb->priorities)
return NULL;
e = av_mallocz(sizeof(*e));
@@ -153,6 +169,10 @@ AVExecutor* ff_executor_alloc(const AVTaskCallbacks *cb, int thread_count)
if (!e->local_contexts)
goto free_executor;
+ e->q = av_calloc(e->cb.priorities, sizeof(Queue));
+ if (!e->q)
+ goto free_executor;
+
e->threads = av_calloc(FFMAX(thread_count, 1), sizeof(*e->threads));
if (!e->threads)
goto free_executor;
@@ -192,16 +212,10 @@ void ff_executor_free(AVExecutor **executor)
void ff_executor_execute(AVExecutor *e, AVTask *t)
{
- AVTaskCallbacks *cb = &e->cb;
- AVTask **prev;
-
if (e->thread_count)
ff_mutex_lock(&e->lock);
- if (t) {
- for (prev = &e->tasks; *prev && cb->priority_higher(*prev, t); prev = &(*prev)->next)
- /* nothing */;
- add_task(prev, t);
- }
+ if (t)
+ add_task(e->q + t->priority % e->cb.priorities, t);
if (e->thread_count) {
ff_cond_signal(&e->cond);
ff_mutex_unlock(&e->lock);
diff --git a/libavcodec/executor.h b/libavcodec/executor.h
index c4688c86e6..9d53534079 100644
--- a/libavcodec/executor.h
+++ b/libavcodec/executor.h
@@ -31,6 +31,7 @@ typedef struct AVExecutor AVExecutor;
typedef struct AVTask AVTask;
struct AVTask {
+ int priority; // task priority should >= 0 and < AVTaskCallbacks.priorities
AVTask *next;
};
@@ -39,8 +40,8 @@ typedef struct AVTaskCallbacks {
int local_context_size;
- // return 1 if a's priority > b's priority
- int (*priority_higher)(const AVTask *a, const AVTask *b);
+ // How many priorities do we have？
+ int priorities;
// run the task
int (*run)(AVTask *t, void *local_context, void *user_data);
diff --git a/libavcodec/vvc/thread.c b/libavcodec/vvc/thread.c
index da7fafed74..a477c06ccb 100644
--- a/libavcodec/vvc/thread.c
+++ b/libavcodec/vvc/thread.c
@@ -103,13 +103,28 @@ typedef struct VVCFrameThread {
AVCond cond;
} VVCFrameThread;
+#define PRIORITY_LOWEST 2
static void add_task(VVCContext *s, VVCTask *t)
{
- VVCFrameThread *ft = t->fc->ft;
+ VVCFrameThread *ft = t->fc->ft;
+ AVTask *task = &t->u.task;
+ const int priorities[] = {
+ 0, // VVC_TASK_STAGE_INIT,
+ 0, // VVC_TASK_STAGE_PARSE,
+ // For an 8K clip, a CTU line completed in the reference frame may trigger 64 and more inter tasks.
+ // We assign these tasks the lowest priority to avoid being overwhelmed with inter tasks.
+ PRIORITY_LOWEST, // VVC_TASK_STAGE_INTER
+ 1, // VVC_TASK_STAGE_RECON,
+ 1, // VVC_TASK_STAGE_LMCS,
+ 1, // VVC_TASK_STAGE_DEBLOCK_V,
+ 1, // VVC_TASK_STAGE_DEBLOCK_H,
+ 1, // VVC_TASK_STAGE_SAO,
+ 1, // VVC_TASK_STAGE_ALF,
+ };
atomic_fetch_add(&ft->nb_scheduled_tasks, 1);
-
- ff_executor_execute(s->executor, &t->u.task);
+ task->priority = priorities[t->stage];
+ ff_executor_execute(s->executor, task);
}
static void task_init(VVCTask *t, VVCTaskStage stage, VVCFrameContext *fc, const int rx, const int ry)
@@ -372,31 +387,6 @@ static int task_is_stage_ready(VVCTask *t, int add)
return task_has_target_score(t, stage, score);
}
-#define CHECK(a, b) \
- do { \
- if ((a) != (b)) \
- return (a) < (b); \
- } while (0)
-
-static int task_priority_higher(const AVTask *_a, const AVTask *_b)
-{
- const VVCTask *a = (const VVCTask*)_a;
- const VVCTask *b = (const VVCTask*)_b;
-
-
- if (a->stage <= VVC_TASK_STAGE_PARSE || b->stage <= VVC_TASK_STAGE_PARSE) {
- CHECK(a->stage, b->stage);
- CHECK(a->fc->decode_order, b->fc->decode_order); //decode order
- CHECK(a->ry, b->ry);
- return a->rx < b->rx;
- }
-
- CHECK(a->fc->decode_order, b->fc->decode_order); //decode order
- CHECK(a->rx + a->ry + a->stage, b->rx + b->ry + b->stage); //zigzag with type
- CHECK(a->rx + a->ry, b->rx + b->ry); //zigzag
- return a->ry < b->ry;
-}
-
static void check_colocation(VVCContext *s, VVCTask *t)
{
const VVCFrameContext *fc = t->fc;
@@ -681,7 +671,7 @@ AVExecutor* ff_vvc_executor_alloc(VVCContext *s, const int thread_count)
AVTaskCallbacks callbacks = {
s,
sizeof(VVCLocalContext),
- task_priority_higher,
+ PRIORITY_LOWEST + 1,
task_run,
};
return ff_executor_alloc(&callbacks, thread_count);
--
2.34.1
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