[vlc-devel] [PATCH 3/3] fingerprinter: use vlc_cond_t instead of sleep

[Alexandre Janniaux]

Hi,

On Sun, Mar 22, 2020 at 05:32:09PM +0200, Rémi Denis-Courmont wrote:
> Le sunnuntaina 22. maaliskuuta 2020, 17.21.22 EET Alexandre Janniaux a écrit :
> > Instead of checking new requests every seconds, wait for actual new
> > requests to be enqueued before trying to do any processing. This avoid
> > the harmful sleep warning
>
> I agree, but what was the rationale for this?

What do you mean? What this?

> > on vlc_tick_sleep as well as providing better
> > latency for new fingerprinting requests on a cold fingerprinter.
> > ---
> >  modules/misc/fingerprinter.c | 22 +++++++++++++++-------
> >  1 file changed, 15 insertions(+), 7 deletions(-)
> >
> > diff --git a/modules/misc/fingerprinter.c b/modules/misc/fingerprinter.c
> > index 99a05346f0..18cc83bc2c 100644
> > --- a/modules/misc/fingerprinter.c
> > +++ b/modules/misc/fingerprinter.c
> > @@ -51,6 +51,8 @@ struct fingerprinter_sys_t
> >          vlc_mutex_t         lock;
> >      } incoming, results;
> >
> > +    vlc_cond_t              incoming_cond;
> > +
> >      struct
> >      {
> >          vlc_array_t         queue;
> > @@ -85,14 +87,13 @@ static int EnqueueRequest( fingerprinter_thread_t *f,
> > fingerprint_request_t *r ) fingerprinter_sys_t *p_sys = f->p_sys;
> >      vlc_mutex_lock( &p_sys->incoming.lock );
> >      int i_ret = vlc_array_append( &p_sys->incoming.queue, r );
> > +    vlc_cond_signal( &p_sys->incoming_cond );
> >      vlc_mutex_unlock( &p_sys->incoming.lock );
> >      return i_ret;
> >  }
> >
> >  static void QueueIncomingRequests( fingerprinter_sys_t *p_sys )
> >  {
> > -    vlc_mutex_lock( &p_sys->incoming.lock );
> > -
> >      for( size_t i = vlc_array_count( &p_sys->incoming.queue ); i > 0 ; i--
> > ) {
> >          fingerprint_request_t *r = vlc_array_item_at_index(
> > &p_sys->incoming.queue, i - 1 ); @@ -100,7 +101,6 @@ static void
> > QueueIncomingRequests( fingerprinter_sys_t *p_sys )
> > fingerprint_request_Delete( r );
> >      }
> >      vlc_array_clear( &p_sys->incoming.queue );
> > -    vlc_mutex_unlock(&p_sys->incoming.lock);
> >  }
> >
> >  static fingerprint_request_t * GetResult( fingerprinter_thread_t *f )
> > @@ -250,6 +250,7 @@ static int Open(vlc_object_t *p_this)
> >
> >      vlc_array_init( &p_sys->incoming.queue );
> >      vlc_mutex_init( &p_sys->incoming.lock );
> > +    vlc_cond_init( &p_sys->incoming_cond );
> >
> >      vlc_array_init( &p_sys->processing.queue );
> >      vlc_cond_init( &p_sys->processing.cond );
> > @@ -344,12 +345,19 @@ static void *Run( void *opaque )
> >      /* main loop */
> >      for (;;)
> >      {
> > -        vlc_tick_sleep( VLC_TICK_FROM_SEC(1) );
> > -
> > -        QueueIncomingRequests( p_sys );
> > -
> >          vlc_testcancel();
>
> This becomes useless.
>
> >
> > +        vlc_mutex_lock( &p_sys->incoming.lock );
> > +        mutex_cleanup_push( &p_sys->incoming.lock );
> > +
> > +        while( vlc_array_count( &p_sys->incoming.queue ) == 0 )
> > +            vlc_cond_wait( &p_sys->incoming_cond, &p_sys->incoming.lock );
> > +
> > +        QueueIncomingRequests( p_sys );
> > +
> > +        vlc_cleanup_pop();
> > +        vlc_mutex_unlock( &p_sys->incoming.lock );
> > +
> >          bool results_available = false;
> >          while( vlc_array_count( &p_sys->processing.queue ) )
> >          {
>
>
> --
> 雷米‧德尼-库尔蒙
> http://www.remlab.net/
>
>
>
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