[FFmpeg-devel] [PATCH 1/2] libavutil/libavfilter: opencl wrapper based on comments on 20130401

[Wei Gao]

2013/4/9 Michael Niedermayer <michaelni at gmx.at>

> On Thu, Apr 04, 2013 at 08:40:10PM +0800, Wei Gao wrote:
> > 2013/4/4 James Almer <jamrial at gmail.com>
> >
> > > On 04/04/13 12:36 AM, Wei Gao wrote:
> > > > 2013/4/4 James Almer <jamrial at gmail.com>
> > > >
> > > >> On 02/04/13 6:46 AM, Michael Niedermayer wrote:
> > > >>>> Since unlike in atomic.c we have init() and uninit() functions
> here,
> > > >> there's no need
> > > >>>> to have a statically allocated mutex. We could call
> > > >> pthread_mutex_init() and
> > > >>>
> > > >>> the init and uninit themselfs must be thread safe, also register is
> > > >>> called before init and must be thread safe
> > > >>
> > > >> As things are right now the code wont compile unless you use
> pthreads or
> > > >> no threading
> > > >> at all (See ticket #2422).
> > > >>
> > > >> So the code either needs to be changed to allocate the mutexes
> > > dynamically
> > > >> (Which will
> > > >> let us use the wrappers), or we make configure abort when trying to
> > > build
> > > >> with OpenCL
> > > >> support and w32threads or os2threads enabled.
> > > >>
> > > >> Ideally, the latter if implemented should be a temporary solution
> until
> > > >> the former is
> > > >> implemented instead.
> > > >>
> > > >> Regards.
> > > >>
> > > > Hi, I want to ask a question, does it mean that the OpenCL code
> can't be
> > > > used  in w32threads or os2threads? Is there any solutions to solve
> that?
> > > > Thanks
> > > > Best regards
> > >
> > > Right now, it fails to compile with anything except pthreads or no
> > > threading at
> > > all: http://ffmpeg.org/trac/ffmpeg/ticket/2422
> > >
> > > And as for a solution, making the mutex dynamic instead of static
> should
> > > allow
> > > us to enable this with all threading types using the wrappers, but I'm
> not
> > > sure how to properly implement that.
> > >
> > > thanks, can I add a function to init the mutex and note that it should
> be
> > called in the main thread to init the mutex? I think codecs also has this
> > problem. I saw that the init function is in pthreads.c, should I add a
> init
> > thread function for opencl in it?
>
> This may be difficult in some use cases
> consider a libA and a libB that both use libavfilter
> a user application using both libA and libB could call either libs
> init function in either order (if they have init functions at all)
>
thanks, michaelni, I am not familiar with threads, is there any
static Mutexs in win32threads and os2threads just like pthreads?
thanks

>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
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> to be. -- Socrates
>
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