[FFmpeg-cvslog] pthread_frame: use atomics for PerThreadContext.state
Anton Khirnov
git at videolan.org
Tue Mar 21 07:41:01 EET 2017
ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Mon Jul 18 00:04:16 2016 +0200| [749262693247808e2db5a2eb29a11ad3cfec211c] | committer: wm4
pthread_frame: use atomics for PerThreadContext.state
Merges Libav commit 64a31b28.
Signed-off-by: wm4 <nfxjfg at googlemail.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=749262693247808e2db5a2eb29a11ad3cfec211c
---
libavcodec/pthread_frame.c | 84 ++++++++++++++++++++++++++--------------------
1 file changed, 47 insertions(+), 37 deletions(-)
diff --git a/libavcodec/pthread_frame.c b/libavcodec/pthread_frame.c
index 272587f..bd25000 100644
--- a/libavcodec/pthread_frame.c
+++ b/libavcodec/pthread_frame.c
@@ -24,6 +24,7 @@
#include "config.h"
+#include <stdatomic.h>
#include <stdint.h>
#include "avcodec.h"
@@ -43,6 +44,25 @@
#include "libavutil/opt.h"
#include "libavutil/thread.h"
+enum {
+ ///< Set when the thread is awaiting a packet.
+ STATE_INPUT_READY,
+ ///< Set before the codec has called ff_thread_finish_setup().
+ STATE_SETTING_UP,
+ /**
+ * Set when the codec calls get_buffer().
+ * State is returned to STATE_SETTING_UP afterwards.
+ */
+ STATE_GET_BUFFER,
+ /**
+ * Set when the codec calls get_format().
+ * State is returned to STATE_SETTING_UP afterwards.
+ */
+ STATE_GET_FORMAT,
+ ///< Set after the codec has called ff_thread_finish_setup().
+ STATE_SETUP_FINISHED,
+};
+
/**
* Context used by codec threads and stored in their AVCodecInternal thread_ctx.
*/
@@ -66,19 +86,7 @@ typedef struct PerThreadContext {
int got_frame; ///< The output of got_picture_ptr from the last avcodec_decode_video() call.
int result; ///< The result of the last codec decode/encode() call.
- enum {
- STATE_INPUT_READY, ///< Set when the thread is awaiting a packet.
- STATE_SETTING_UP, ///< Set before the codec has called ff_thread_finish_setup().
- STATE_GET_BUFFER, /**<
- * Set when the codec calls get_buffer().
- * State is returned to STATE_SETTING_UP afterwards.
- */
- STATE_GET_FORMAT, /**<
- * Set when the codec calls get_format().
- * State is returned to STATE_SETTING_UP afterwards.
- */
- STATE_SETUP_FINISHED ///< Set after the codec has called ff_thread_finish_setup().
- } state;
+ atomic_int state;
/**
* Array of frames passed to ff_thread_release_buffer().
@@ -133,8 +141,8 @@ static attribute_align_arg void *frame_worker_thread(void *arg)
pthread_mutex_lock(&p->mutex);
while (1) {
- while (p->state == STATE_INPUT_READY && !p->die)
- pthread_cond_wait(&p->input_cond, &p->mutex);
+ while (atomic_load(&p->state) == STATE_INPUT_READY && !p->die)
+ pthread_cond_wait(&p->input_cond, &p->mutex);
if (p->die) break;
@@ -152,7 +160,8 @@ static attribute_align_arg void *frame_worker_thread(void *arg)
av_frame_unref(p->frame);
}
- if (p->state == STATE_SETTING_UP) ff_thread_finish_setup(avctx);
+ if (atomic_load(&p->state) == STATE_SETTING_UP)
+ ff_thread_finish_setup(avctx);
pthread_mutex_lock(&p->progress_mutex);
#if 0 //BUFREF-FIXME
@@ -162,7 +171,7 @@ static attribute_align_arg void *frame_worker_thread(void *arg)
p->progress[i][1] = INT_MAX;
}
#endif
- p->state = STATE_INPUT_READY;
+ atomic_store(&p->state, STATE_INPUT_READY);
pthread_cond_broadcast(&p->progress_cond);
pthread_cond_signal(&p->output_cond);
@@ -323,9 +332,9 @@ static int submit_packet(PerThreadContext *p, AVPacket *avpkt)
if (prev_thread) {
int err;
- if (prev_thread->state == STATE_SETTING_UP) {
+ if (atomic_load(&prev_thread->state) == STATE_SETTING_UP) {
pthread_mutex_lock(&prev_thread->progress_mutex);
- while (prev_thread->state == STATE_SETTING_UP)
+ while (atomic_load(&prev_thread->state) == STATE_SETTING_UP)
pthread_cond_wait(&prev_thread->progress_cond, &prev_thread->progress_mutex);
pthread_mutex_unlock(&prev_thread->progress_mutex);
}
@@ -345,7 +354,7 @@ static int submit_packet(PerThreadContext *p, AVPacket *avpkt)
return ret;
}
- p->state = STATE_SETTING_UP;
+ atomic_store(&p->state, STATE_SETTING_UP);
pthread_cond_signal(&p->input_cond);
pthread_mutex_unlock(&p->mutex);
@@ -358,13 +367,13 @@ static int submit_packet(PerThreadContext *p, AVPacket *avpkt)
if (!p->avctx->thread_safe_callbacks && (
p->avctx->get_format != avcodec_default_get_format ||
p->avctx->get_buffer2 != avcodec_default_get_buffer2)) {
- while (p->state != STATE_SETUP_FINISHED && p->state != STATE_INPUT_READY) {
+ while (atomic_load(&p->state) != STATE_SETUP_FINISHED && atomic_load(&p->state) != STATE_INPUT_READY) {
int call_done = 1;
pthread_mutex_lock(&p->progress_mutex);
- while (p->state == STATE_SETTING_UP)
+ while (atomic_load(&p->state) == STATE_SETTING_UP)
pthread_cond_wait(&p->progress_cond, &p->progress_mutex);
- switch (p->state) {
+ switch (atomic_load_explicit(&p->state, memory_order_acquire)) {
case STATE_GET_BUFFER:
p->result = ff_get_buffer(p->avctx, p->requested_frame, p->requested_flags);
break;
@@ -376,7 +385,7 @@ static int submit_packet(PerThreadContext *p, AVPacket *avpkt)
break;
}
if (call_done) {
- p->state = STATE_SETTING_UP;
+ atomic_store(&p->state, STATE_SETTING_UP);
pthread_cond_signal(&p->progress_cond);
}
pthread_mutex_unlock(&p->progress_mutex);
@@ -431,9 +440,9 @@ int ff_thread_decode_frame(AVCodecContext *avctx,
do {
p = &fctx->threads[finished++];
- if (p->state != STATE_INPUT_READY) {
+ if (atomic_load(&p->state) != STATE_INPUT_READY) {
pthread_mutex_lock(&p->progress_mutex);
- while (p->state != STATE_INPUT_READY)
+ while (atomic_load_explicit(&p->state, memory_order_relaxed) != STATE_INPUT_READY)
pthread_cond_wait(&p->output_cond, &p->progress_mutex);
pthread_mutex_unlock(&p->progress_mutex);
}
@@ -516,11 +525,12 @@ void ff_thread_finish_setup(AVCodecContext *avctx) {
if (!(avctx->active_thread_type&FF_THREAD_FRAME)) return;
pthread_mutex_lock(&p->progress_mutex);
- if(p->state == STATE_SETUP_FINISHED){
+ if(atomic_load(&p->state) == STATE_SETUP_FINISHED){
av_log(avctx, AV_LOG_WARNING, "Multiple ff_thread_finish_setup() calls\n");
}
- p->state = STATE_SETUP_FINISHED;
+ atomic_store(&p->state, STATE_SETUP_FINISHED);
+
pthread_cond_broadcast(&p->progress_cond);
pthread_mutex_unlock(&p->progress_mutex);
}
@@ -533,9 +543,9 @@ static void park_frame_worker_threads(FrameThreadContext *fctx, int thread_count
for (i = 0; i < thread_count; i++) {
PerThreadContext *p = &fctx->threads[i];
- if (p->state != STATE_INPUT_READY) {
+ if (atomic_load(&p->state) != STATE_INPUT_READY) {
pthread_mutex_lock(&p->progress_mutex);
- while (p->state != STATE_INPUT_READY)
+ while (atomic_load(&p->state) != STATE_INPUT_READY)
pthread_cond_wait(&p->output_cond, &p->progress_mutex);
pthread_mutex_unlock(&p->progress_mutex);
}
@@ -753,7 +763,7 @@ void ff_thread_flush(AVCodecContext *avctx)
int ff_thread_can_start_frame(AVCodecContext *avctx)
{
PerThreadContext *p = avctx->internal->thread_ctx;
- if ((avctx->active_thread_type&FF_THREAD_FRAME) && p->state != STATE_SETTING_UP &&
+ if ((avctx->active_thread_type&FF_THREAD_FRAME) && atomic_load(&p->state) != STATE_SETTING_UP &&
(avctx->codec->update_thread_context || !THREAD_SAFE_CALLBACKS(avctx))) {
return 0;
}
@@ -772,7 +782,7 @@ static int thread_get_buffer_internal(AVCodecContext *avctx, ThreadFrame *f, int
if (!(avctx->active_thread_type & FF_THREAD_FRAME))
return ff_get_buffer(avctx, f->f, flags);
- if (p->state != STATE_SETTING_UP &&
+ if (atomic_load(&p->state) != STATE_SETTING_UP &&
(avctx->codec->update_thread_context || !THREAD_SAFE_CALLBACKS(avctx))) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() cannot be called after ff_thread_finish_setup()\n");
return -1;
@@ -797,10 +807,10 @@ static int thread_get_buffer_internal(AVCodecContext *avctx, ThreadFrame *f, int
pthread_mutex_lock(&p->progress_mutex);
p->requested_frame = f->f;
p->requested_flags = flags;
- p->state = STATE_GET_BUFFER;
+ atomic_store_explicit(&p->state, STATE_GET_BUFFER, memory_order_release);
pthread_cond_broadcast(&p->progress_cond);
- while (p->state != STATE_SETTING_UP)
+ while (atomic_load(&p->state) != STATE_SETTING_UP)
pthread_cond_wait(&p->progress_cond, &p->progress_mutex);
err = p->result;
@@ -825,16 +835,16 @@ enum AVPixelFormat ff_thread_get_format(AVCodecContext *avctx, const enum AVPixe
if (!(avctx->active_thread_type & FF_THREAD_FRAME) || avctx->thread_safe_callbacks ||
avctx->get_format == avcodec_default_get_format)
return ff_get_format(avctx, fmt);
- if (p->state != STATE_SETTING_UP) {
+ if (atomic_load(&p->state) != STATE_SETTING_UP) {
av_log(avctx, AV_LOG_ERROR, "get_format() cannot be called after ff_thread_finish_setup()\n");
return -1;
}
pthread_mutex_lock(&p->progress_mutex);
p->available_formats = fmt;
- p->state = STATE_GET_FORMAT;
+ atomic_store(&p->state, STATE_GET_FORMAT);
pthread_cond_broadcast(&p->progress_cond);
- while (p->state != STATE_SETTING_UP)
+ while (atomic_load(&p->state) != STATE_SETTING_UP)
pthread_cond_wait(&p->progress_cond, &p->progress_mutex);
res = p->result_format;
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