On Tue, 2018-07-24 at 09:53 -0700, Dmitry Rogozhkin wrote:
> 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;
Never do something 2 mins before the meeting. This should probably be:
if (!s->session_download_init) {
qsv_init_internal_session(ctx, &s->session_download, 0);
if (s->session_download)
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;
And here:
if (!s->session_upload_init) {
qsv_init_internal_session(ctx, &s->session_upload, 0);
if (s->session_upload)
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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