[FFmpeg-devel] [BASIC QUESTION] Profiling tool for ffmpeg

[FFmpeg-devel] [BASIC QUESTION] Profiling tool for ffmpeg

[Cesar Matheus]

Hi, I'm a CS student working on an optimisation of the ebur128 filter. First I'm looking for the nicest way to get information on code performance.
I saw  that the configuration flag   "--enable-linux-perf"      enables Linux Performance Monitor API, I've been using the perf tool with the following commands for example :

./perf record -F 99 -a -g --call-graph dwarf ./ffmpeg -i test.wav -vn -af loudnorm=print_format=summary:dual_mono=true -f null /dev/null

but I'm not quite satisfate with the result. 

Do you have any advice on how to properly extract informations such as execution time, function call graph etc.. in such a case using profiling tool (perf or gprof for example ?

Thank you very much,
César Mathéus
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Re: [FFmpeg-devel] [BASIC QUESTION] Profiling tool for ffmpeg

[Kieran Kunhya via ffmpeg-devel]

On Mon, 24 Feb 2025, 06:43 Cesar Matheus, <cesar.matheus@telecom-paris.fr>
wrote:

> Hi, I'm a CS student working on an optimisation of the ebur128 filter.
> First I'm looking for the nicest way to get information on code performance.
> I saw  that the configuration flag   "--enable-linux-perf"      enables
> Linux Performance Monitor API, I've been using the perf tool with the
> following commands for example :
>
> ./perf record -F 99 -a -g --call-graph dwarf ./ffmpeg -i test.wav -vn -af
> loudnorm=print_format=summary:dual_mono=true -f null /dev/null
>
> but I'm not quite satisfate with the result.
>
> Do you have any advice on how to properly extract informations such as
> execution time, function call graph etc.. in such a case using profiling
> tool (perf or gprof for example ?
>
> Thank you very much,
> César Mathéus
>

Hi Cesar,

You should profile with the "ffmpeg_g" command which contains debug symbols.

Kieran

>
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Re: [FFmpeg-devel] [BASIC QUESTION] Profiling tool for ffmpeg

[Devin Heitmueller]

On Mon, Feb 24, 2025 at 9:43 AM Cesar Matheus
<cesar.matheus@telecom-paris.fr> wrote:
>
> Hi, I'm a CS student working on an optimisation of the ebur128 filter. First I'm looking for the nicest way to get information on code performance.
> I saw  that the configuration flag   "--enable-linux-perf"      enables Linux Performance Monitor API, I've been using the perf tool with the following commands for example :
>
> ./perf record -F 99 -a -g --call-graph dwarf ./ffmpeg -i test.wav -vn -af loudnorm=print_format=summary:dual_mono=true -f null /dev/null
>
> but I'm not quite satisfate with the result.
>
> Do you have any advice on how to properly extract informations such as execution time, function call graph etc.. in such a case using profiling tool (perf or gprof for example ?

I've had excellent success with Intel VTune, which while not open
source is freely available:

https://www.intel.com/content/www/us/en/developer/tools/oneapi/vtune-profiler.html#gs.k0kfve

Function call timing, memory bandwidth utilization (if on an Intel
CPU), cache analysis, and very easy to get up and running.  The hard
part is understanding the results, but the GUI makes that *much*
easier than any command line perf based solution.

But yeah, as Kieran pointed out, for any of these solutions you should
be using the version of the ffmpeg binary that contains debug info.

Devin

-- 
Devin Heitmueller, Senior Software Engineer
LTN Global Communications
o: +1 (301) 363-1001
w: https://ltnglobal.com  e: devin.heitmueller@ltnglobal.com
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Re: [FFmpeg-devel] [BASIC QUESTION] Profiling tool for ffmpeg

[Stone Chen]

On Mon, Feb 24, 2025 at 9:54 AM Devin Heitmueller <
devin.heitmueller@ltnglobal.com> wrote:

> On Mon, Feb 24, 2025 at 9:43 AM Cesar Matheus
> <cesar.matheus@telecom-paris.fr> wrote:
> >
> > Hi, I'm a CS student working on an optimisation of the ebur128 filter.
> First I'm looking for the nicest way to get information on code performance.
> > I saw  that the configuration flag   "--enable-linux-perf"      enables
> Linux Performance Monitor API, I've been using the perf tool with the
> following commands for example :
> >
> > ./perf record -F 99 -a -g --call-graph dwarf ./ffmpeg -i test.wav -vn
> -af loudnorm=print_format=summary:dual_mono=true -f null /dev/null
> >
> > but I'm not quite satisfate with the result.
> >
> > Do you have any advice on how to properly extract informations such as
> execution time, function call graph etc.. in such a case using profiling
> tool (perf or gprof for example ?
>
> I've had excellent success with Intel VTune, which while not open
> source is freely available:
>
>
> https://www.intel.com/content/www/us/en/developer/tools/oneapi/vtune-profiler.html#gs.k0kfve


AMD equivalent, though not nearly as nice as VTune imo.

https://www.amd.com/en/developer/uprof.html

<https://www.intel.com/content/www/us/en/developer/tools/oneapi/vtune-profiler.html#gs.k0kfve>
>
> Function call timing, memory bandwidth utilization (if on an Intel
> CPU), cache analysis, and very easy to get up and running.  The hard
> part is understanding the results, but the GUI makes that *much*
> easier than any command line perf based solution.
>
> But yeah, as Kieran pointed out, for any of these solutions you should
> be using the version of the ffmpeg binary that contains debug info.
>
> Devin
>
> --
> Devin Heitmueller, Senior Software Engineer
> LTN Global Communications
> o: +1 (301) 363-1001
> w: https://ltnglobal.com  e: devin.heitmueller@ltnglobal.com
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel@ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".
>
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