[FFmpeg-devel] [PATCH] updated documentation for -opencl_bench option

Stefano Sabatini stefasab at gmail.com
Tue Jan 27 12:08:29 CET 2015


On date Tuesday 2015-01-27 09:56:41 +0000, Gupta, Maneesh encoded:
> Attached is a patch for updated documentation for the -opencl_bench option.
> 
> Regards,
> Maneesh

> From 5c963436f67cc2fe6eae93f0fbda588e902f2da4 Mon Sep 17 00:00:00 2001
> From: Maneesh Gupta <maneesh.gupta at amd.com>
> Date: Tue, 27 Jan 2015 15:09:41 +0530
> Subject: [PATCH] documentation for -opencl_bench
> 
> ---
>  doc/fftools-common-opts.texi | 31 +++++++++++++++++++++++++++++--
>  1 file changed, 29 insertions(+), 2 deletions(-)
> 
> diff --git a/doc/fftools-common-opts.texi b/doc/fftools-common-opts.texi
> index 7d52c1a..876c53c 100644
> --- a/doc/fftools-common-opts.texi
> +++ b/doc/fftools-common-opts.texi
> @@ -294,8 +294,35 @@ Possible flags for this option are:
>  @end table
>  
>  @item -opencl_bench
> -Benchmark all available OpenCL devices and show the results. This option
> -is only available when FFmpeg has been compiled with @code{--enable-opencl}.
> +This option is used to benchmark all available OpenCL devices and print the
> +results. This option is only available when FFmpeg has been compiled with
> + at code{--enable-opencl}.
> +
> +When FFmpeg is configured with @code{--enable-opencl}, the options for the
> +global OpenCL context are set via @code{-opencl_options}. See the
> +``OpenCL Options`` section in the ffmpeg-utils manual for the complete list of
> +supported options. Amongst others, these options include the ability to select
> +a specific platform and device to run the OpenCL code on. By default, FFmpeg
> +will run on the first device of the first platform. While the options for the
> +global OpenCL context provide flexibility to the user in selecting the OpenCL
> +device of their choice, most users would probably want to select the fastest
> +OpenCL device for their system.
> +

> +This option assists the selection of the most efficient configuration by
> +identifying the appropriate device for the user?s system. The built-in

unrecognized character here, use '

> +benchmark is run on all the OpenCL devices and the performance is measured for
> +each device. The devices in the results list are sorted based on their
> +performance with the fastest device listed first. The user can subsequently

> +invoke Ffmpeg using the device deemed most appropriate via

@command{ffmpeg}

> + at code{--opencl_options} to obtain the best performance for the OpenCL

@option{-opencl_options}

> +accelerated code.
> +
> +Typical usage to use the fastest OpenCL device involve the following steps:
> + at example
> +ffmpeg -opencl_bench

Close the example, or comment with # the next comment line.

> +Note down the platform ID (@var{pIDx}) & device ID (@var{dIDx}) of the first i.e. fastest device in the list.

> +ffmpeg -opencl_options platform_idx=@var{pIDx}:device_idx=@var{dIDx} ...
> + at end example

I'd write something like this:

----8<--------------------
Typical usage to use the fastest OpenCL device involve the following steps.

Run the command:
@example
ffmpeg -opencl_bench
@end example

Note down the platform ID (@var{pidx}) and device index (@var{didx})
of the first i.e. fastest device in the list.

Select the platform and device using the command:
@example
ffmpeg -opencl_options platform_idx=@var{pidx}:device_idx=@var{didx} ...
@end example
----8<--------------------

LGTM otherwise, thanks.
-- 
FFmpeg = Foolish and Fancy Magic Powered Educated Gnome


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