[FFmpeg-devel] [PATCH] configure: set IceLake-AVX512 as the minimum baseline

[qs xw]

Ronald Wrote:

> On Tue, Aug 17, 2021 at 10:13 PM Wu, Jianhua <jianhua.wu at intel.com<https://ffmpeg.org/mailman/listinfo/ffmpeg-devel>> wrote:



> > The reason why we set the icelake-avx512 as the minimum baseline is that

> > we don't want FFmpeg run on a processor downclocking heavily, hence, keep

> > the current flag and add a new AVX512ICL make no sense.

> >

>

> I don't think you can make that decision single-handedly. doesn't it depend

> on the situation, and shouldn't individual users and/or developers be able

> to make that decision themselves?

>

> And still, you're adjusting the assembler check, you need to adjust the

> runtime check. This won't do what you think it does. It's not a runtime

> check and doesn't check host runtime abilities, just host build abilities.

Hi Ronald,

I didn't make the decision single-handedly, do not, and will not do.
I just followed the suggestions from the maintainers of FFmpeg. I
think you might be able to check more details follow these three
archived links:
http://ffmpeg.org/pipermail/ffmpeg-devel/2021-August/283869.html
http://ffmpeg.org/pipermail/ffmpeg-devel/2021-August/283878.html
http://ffmpeg.org/pipermail/ffmpeg-devel/2021-August/283872.html

And about the runtime check of cpuid, I have updated the v2 patches
today. Please check this for more details.
http://ffmpeg.org/pipermail/ffmpeg-devel/2021-August/283973.html

It seemed that there are different perspectives from maintainers
of the community. And I was supposed to clarify here that I follow
the FFmpeg contribution checklist and use the AVX512 invoking
conventions in libavutil/cpu in FFmpeg to submit a patchset about
optimization Gaussian Blur with AVX2 and AVX512. And I have been
actively communicating and accepting the suggestions from the
mail-list to fix and improve what I could do for the patches.

By the way, I have emphasized that using AVX512 is not mandatory
at the beginning. Use or not depends on users and developers.
The options that disable and enable AVX512 have already been provided
by FFmpeg. Here are more details:
http://ffmpeg.org/pipermail/ffmpeg-devel/2021-August/283587.html

So what should I do? Feel free to let me know.

Best regards.
Jianhua