[libav-devel] [v5] qsvvpp: Fix to perform full init only when needed

Rogozhkin, Dmitry V dmitry.v.rogozhkin at intel.com
Thu Aug 23 22:51:06 CEST 2018


On Wed, 2018-07-25 at 16:14 +0000, Rogozhkin, Dmitry V wrote:
> 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 <maxim.d33 at gmail.com>
> > > ---
> > >  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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Maxim, did you miss these comments? or I missed a reply?


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