On Wed, 2018-07-18 at 14:07 +0200, Maxym Dmytrychenko wrote:
> Not used VPP sessions, like for hwupload/hwdownload handling,
> can increase CPU utilization and this patch fixes it.
> thank you,Joe, for the contribution.
>
> Signed-off-by: Maxym Dmytrychenko <[email protected]>
> ---
> libavutil/hwcontext_qsv.c | 72
> +++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 64 insertions(+), 8 deletions(-)
>
> diff --git a/libavutil/hwcontext_qsv.c b/libavutil/hwcontext_qsv.c
> index b3eb4a3ea..6bc2a38ff 100644
> --- a/libavutil/hwcontext_qsv.c
> +++ b/libavutil/hwcontext_qsv.c
> @@ -23,6 +23,10 @@
>
> #include "config.h"
>
> +#if HAVE_PTHREADS
> +#include <pthread.h>
> +#endif
> +
> #if CONFIG_VAAPI
> #include "hwcontext_vaapi.h"
> #endif
> @@ -56,7 +60,13 @@ typedef struct QSVDeviceContext {
>
> typedef struct QSVFramesContext {
> mfxSession session_download;
> + int session_download_init;
> mfxSession session_upload;
> + int session_upload_init;
> +#if HAVE_PTHREADS
> + pthread_mutex_t session_lock;
> + pthread_cond_t session_cond;
> +#endif
>
> AVBufferRef *child_frames_ref;
> mfxFrameSurface1 *surfaces_internal;
> @@ -146,13 +156,20 @@ static void qsv_frames_uninit(AVHWFramesContext
> *ctx)
> MFXVideoVPP_Close(s->session_download);
> MFXClose(s->session_download);
> }
> - s->session_download = NULL;
> + s->session_download = NULL;
> + s->session_download_init = 0;
>
> if (s->session_upload) {
> MFXVideoVPP_Close(s->session_upload);
> MFXClose(s->session_upload);
> }
> - s->session_upload = NULL;
> + s->session_upload = NULL;
> + s->session_upload_init = 0;
> +
> +#if HAVE_PTHREADS
> + pthread_mutex_destroy(&s->session_lock);
> + pthread_cond_destroy(&s->session_cond);
> +#endif
>
> av_freep(&s->mem_ids);
> av_freep(&s->surface_ptrs);
> @@ -535,13 +552,16 @@ static int qsv_frames_init(AVHWFramesContext
> *ctx)
> s->mem_ids[i] = frames_hwctx->surfaces[i].Data.MemId;
> }
>
> - ret = qsv_init_internal_session(ctx, &s->session_download, 0);
> - if (ret < 0)
> - return ret;
> + s->session_download = NULL;
> + s->session_upload = NULL;
>
> - ret = qsv_init_internal_session(ctx, &s->session_upload, 1);
> - if (ret < 0)
> - return ret;
> + s->session_download_init = 0;
> + s->session_upload_init = 0;
> +
> +#if HAVE_PTHREADS
> + pthread_mutex_init(&s->session_lock, NULL);
> + pthread_cond_init(&s->session_cond, NULL);
> +#endif
>
> return 0;
> }
> @@ -741,6 +761,24 @@ static int
> qsv_transfer_data_from(AVHWFramesContext *ctx, AVFrame *dst,
> mfxSyncPoint sync = NULL;
> mfxStatus err;
>
> + while (!s->session_download_init && !s->session_download) {
> +#if HAVE_PTHREADS
> + if (pthread_mutex_trylock(&s->session_lock) == 0) {
> +#endif
> + qsv_init_internal_session(ctx, &s->session_download, 0);
> + s->session_download_init = 1;
> +#if HAVE_PTHREADS
> + pthread_cond_signal(&s->session_cond);
You don't need to signal under the mutex. More efficiently is to do
that without.
> + pthread_mutex_unlock(&s->session_lock);
> + }
> + else {
> + pthread_mutex_lock(&s->session_lock);
> + pthread_cond_wait(&s->session_cond, &s->session_lock);
This is incorrect usage of condition variables. Look into example in
'man 3 pthread_cond_wait': you should check predicate under the mutex.
> + pthread_mutex_unlock(&s->session_lock);
> + }
> +#endif
> + }
> +
As I said the above code is an example of incorrect usage of condition
variables. I believe this should be written in this way:
#if HAVE_PTHREADS
if (pthread_mutex_trylock(&s->session_lock) == 0) {
#endif
qsv_init_internal_session(ctx, &s->session_download, 0);
s->session_download_init = 1;
#if HAVE_PTHREADS
pthread_mutex_unlock(&s->session_lock);
pthread_cond_signal(&s->session_cond);
} else {
pthread_mutex_lock(&s->session_lock);
while (!s->session_download_init && !s->session_download) {
pthread_cond_wait(&s->session_cond, &s->session_lock);
}
pthread_mutex_unlock(&s->session_lock);
}
#endif
>
> if (!s->session_download) {
> if (s->child_frames_ref)
> return qsv_transfer_data_child(ctx, dst, src);
> @@ -788,6 +826,24 @@ static int
> qsv_transfer_data_to(AVHWFramesContext *ctx, AVFrame *dst,
> mfxSyncPoint sync = NULL;
> mfxStatus err;
>
> + while (!s->session_upload_init && !s->session_upload) {
> +#if HAVE_PTHREADS
> + if (pthread_mutex_trylock(&s->session_lock) == 0) {
> +#endif
> + qsv_init_internal_session(ctx, &s->session_upload, 1);
> + s->session_upload_init = 1;
> +#if HAVE_PTHREADS
> + pthread_cond_signal(&s->session_cond);
> + pthread_mutex_unlock(&s->session_lock);
> + }
> + else {
> + pthread_mutex_lock(&s->session_lock);
> + pthread_cond_wait(&s->session_cond, &s->session_lock);
> + pthread_mutex_unlock(&s->session_lock);
> + }
> +#endif
> + }
> +
Same comment as above. Correct code would be:
#if HAVE_PTHREADS
if (pthread_mutex_trylock(&s->session_lock) == 0) {
#endif
qsv_init_internal_session(ctx, &s->session_upload, 0);
s->session_upload_init = 1;
#if HAVE_PTHREADS
pthread_mutex_unlock(&s->session_lock);
pthread_cond_signal(&s->session_cond);
} else {
pthread_mutex_lock(&s->session_lock);
while (!s->session_upload_init && !s->session_upload) {
pthread_cond_wait(&s->session_cond, &s->session_lock);
}
pthread_mutex_unlock(&s->session_lock);
}
#endif
> if (!s->session_upload) {
> if (s->child_frames_ref)
> return qsv_transfer_data_child(ctx, dst, src);
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