[FFmpeg-devel] [PATCH]opencl: automatically select the fastest opencl device

[Michael Niedermayer]

On Fri, Dec 06, 2013 at 02:35:19PM -0600, Lenny Wang wrote:
> On Fri, Dec 6, 2013 at 4:57 AM, Stefano Sabatini <stefasab at gmail.com> wrote:
> > On date Friday 2013-12-06 03:00:09 -0600, Lenny Wang encoded:
> >> >
> >> > please move the opencl code from cmdutils.c into a seperate file
> >> > its up to you and wei if you want the benchmarking and or listing
> >> > code available from the ffmpeg tool or in a seperate tool. but
> >> > opencl code should not be put in random files under ifdef, put it
> >> > in seperate opencl specific files. build and link them only when
> >> > opencl is available
> >> >
> >>
> >> Sorry about the late reply.  Please review attached patch modified
> >> based on Michael's suggestion, thanks.
> >
> >> From: Lenny Wang <lwanghpc at gmail.com>
> >> Date: Fri, 6 Dec 2013 02:40:00 -0600
> >> Subject: [PATCH] cmdutils & opencl: add -opencl_bench option to test and show available OpenCL devices
> >>
> >> ---
> >>  Makefile                     |   1 +
> >>  cmdutils.c                   |  54 +++++++++++-
> >>  cmdutils.h                   |   6 ++
> >>  cmdutils_common_opts.h       |   1 +
> >>  doc/APIchanges               |   2 +
> >>  doc/fftools-common-opts.texi |   4 +
> >>  doc/utils.texi               |   4 +-
> >>  libavutil/opencl.c           |  42 ++++++++++
> >>  libavutil/opencl.h           |  16 ++++
> >>  libavutil/version.h          |   2 +-
> >>  tools/opencl_bench.c         | 194 +++++++++++++++++++++++++++++++++++++++++++
> >>  tools/opencl_bench.h         |  37 +++++++++
> >>  12 files changed, 359 insertions(+), 4 deletions(-)
> >
> > Uh, not yet.
> >
> > So, Michael suggested to move all cmdutils OpenCL code to a separate
> > file. The tools directory is meant for self-contained tools, you
> > should not depend on ff*/cmdutils code or even worse make ff*/cmdutils
> > code depend on it.
> >
> > So I suggest this: you move all cmdutils OpenCL code to
> > cmdutils_opencl.c/h. cmdutils_opencl.o will be linked only if OpenCL
> > is detected. The opencl_options code should go in the same file as
> > well (in the same or maybe in a separate follow-up patch).
> >
> > Function prototypes can go to a dedicated cmdutils_opencl.h file or
> > stay in cmdutils.h, under #ifdef, as Michael prefers.
> 
> Fixed based on Stefano's suggestion.

>  Makefile                     |    1 
>  cmdutils.c                   |   24 ---
>  cmdutils.h                   |    4 
>  cmdutils_common_opts.h       |    1 
>  cmdutils_opencl.c            |  274 +++++++++++++++++++++++++++++++++++++++++++
>  doc/APIchanges               |    2 
>  doc/fftools-common-opts.texi |    4 
>  doc/utils.texi               |    4 
>  libavutil/opencl.c           |   42 ++++++
>  libavutil/opencl.h           |   16 ++
>  10 files changed, 346 insertions(+), 26 deletions(-)
> 79e5ef131086be7343651bede013cea722dcaaf2  cmdutils_opencl.patch
> From: Lenny Wang <lwanghpc at gmail.com>
> Date: Fri, 6 Dec 2013 14:20:00 -0600
> Subject: [PATCH] cmdutils & opencl: add cmdutils_opencl.c with new -opencl_bench option
[...]

> +    start = av_gettime();
> +    for (i = 0; i < OPENCL_NB_ITER; i++)
> +	    OCLCHECK(clEnqueueNDRangeKernel, ext_opencl_env->command_queue, kernel, 2, NULL,
> +                 global_work_size_2d, local_work_size_2d, 0, NULL, NULL);
> +	clFinish(ext_opencl_env->command_queue);
> +    ret = (av_gettime() - start)/OPENCL_NB_ITER;

tabs are forbidden in ffmpeg git


[...]
> diff --git a/doc/APIchanges b/doc/APIchanges
> index 08ba47f..5b0de25 100644
> --- a/doc/APIchanges
> +++ b/doc/APIchanges
> @@ -14,6 +14,8 @@ libavutil:     2012-10-22
>  
>  
>  API changes, most recent first:
> +2013-12-xx - xxxxxxx - lavu 52.57.100 - opencl.h
> +  Add av_opencl_benchmark() function.

version.h bump missing


[...]
> diff --git a/libavutil/opencl.h b/libavutil/opencl.h
> index e4ecbf8..cf0abd7 100644
> --- a/libavutil/opencl.h
> +++ b/libavutil/opencl.h
> @@ -310,4 +310,20 @@ void av_opencl_release_kernel(AVOpenCLKernelEnv *env);
>   */
>  void av_opencl_uninit(void);
>  
> +/**
> + * Benchmark an OpenCL device with a user defined callback function.  This function
> + * sets up an external OpenCL environment including context and command queue on
> + * the device then tears it down in the end.  The callback function should perform
> + * the rest of the work.
> + *
> + * @param device            pointer to the OpenCL device to be used
> + * @param platform          cl_platform_id handle to which the device belongs to
> + * @param benchmark         callback function to perform the benchmark, return a
> + *                          negative value in case of failure
> + * @return the score passed from the callback function, a negative error code in case
> + * of failure
> + */
> +int64_t av_opencl_benchmark(AVOpenCLDeviceNode *device, cl_platform_id platform,
> +                            int64_t (*benchmark)(AVOpenCLExternalEnv *ext_opencl_env));

why is this in libavutil ?
that is why is the benchmark code split between cmdutils_opencl
and libavutil ?

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Into a blind darkness they enter who follow after the Ignorance,
they as if into a greater darkness enter who devote themselves
to the Knowledge alone. -- Isha Upanishad
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