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

Michael Niedermayer michaelni at gmx.at
Mon Dec 9 05:30:26 CET 2013


On Sun, Dec 08, 2013 at 09:03:57PM -0600, Lenny Wang wrote:
> On Sun, Dec 8, 2013 at 8:13 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > 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 ?
> >
> 
> We decided to make the benchmark API public so other library
> developers can also take advantage of it.  Stefano and Wei agreed with
> the design in previous discussions.

>  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 ++
>  libavutil/version.h          |    2 
>  11 files changed, 347 insertions(+), 27 deletions(-)
> d244659a9e5e94c86f24d91c46af79ff59868ec2  add-opencl-bench-option.patch
> From: Lenny Wang <lwanghpc at gmail.com>
> Date: Sun, 8 Dec 2013 21:01:00 -0600
> Subject: [PATCH] cmdutils & opencl: add -opencl_bench option to test and show available OpenCL devices

should be ok
wei ?

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No great genius has ever existed without some touch of madness. -- Aristotle
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