From: Thomas Petazzoni via buildroot <buildroot@buildroot.org>
To: Vincent Fazio <vfazio@gmail.com>
Cc: buildroot@buildroot.org
Subject: Re: [Buildroot] [PATCH 1/1] arch/Config.in.x86: add Intel and AMD GCC targets
Date: Sun, 30 Jul 2023 23:01:51 +0200 [thread overview]
Message-ID: <20230730230151.5a1de6c2@windsurf> (raw)
In-Reply-To: <20230730173242.6669-1-vfazio@gmail.com>
Hello Vincent,
On Sun, 30 Jul 2023 12:32:42 -0500
Vincent Fazio <vfazio@gmail.com> wrote:
> Sync the CPU target list with what's available up to GCC 13.
>
> Multiple references used for flags and synonyms [0] [1] [2] [3].
>
> [0]: https://gcc.gnu.org/onlinedocs/gcc-13.2.0/gcc/x86-Options.html
> [1]: https://gcc.gnu.org/git/?p=gcc.git;a=blob_plain;f=gcc/config/i386/i386.h;hb=refs/tags/releases/gcc-13.2.0
> [2]: https://gcc.gnu.org/git/?p=gcc.git;a=blob_plain;f=gcc/common/config/i386/i386-common.cc;hb=refs/tags/releases/gcc-13.2.0
> [3]: https://en.wikipedia.org/wiki/AVX-512#CPUs_with_AVX-512
>
> Signed-off-by: Vincent Fazio <vfazio@gmail.com>
It generally looks good (even though I definitely didn't check all the
CPUs and their capabilities, I trust you). However, I have one comment.
> +# BR2_X86_CPU_HAS_AVX512 is used to enable the x86_64-v4 toolchain(s).
I think this wording is not good. BR2_X86_CPU_HAS_AVX512 is not *used*
to enable the x86-86-v4 toolchain. This option is not there for that.
This hidden option is here to allow the CPU variants that support
AVX512 to indicate that they do offer this support. It has nothing to
with the x86-86-v4 toolchain per-se.
> +# Some CPUs have a _subset_ of AVX512, but do not meet the minimum requirements
> +# for x86_64-v4 (AVX512F, AVX512BW, AVX512CD, AVX512DQ, AVX512VL).
> +# Reference: https://en.wikipedia.org/wiki/AVX-512#CPUs_with_AVX-512
I think a better wording is:
# CPU variants should only select this option if they support for the
# full set of AVX512 instructions: AVX512F, AVX512BW, AVX512CD, AVX512DQ,
# AVX512VL
Please note that if this is not a good choice, we can also revisit how
the AVX512 support is handled.
> config BR2_X86_CPU_HAS_AVX512
> bool
Thanks!
Thomas
--
Thomas Petazzoni, co-owner and CEO, Bootlin
Embedded Linux and Kernel engineering and training
https://bootlin.com
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next prev parent reply other threads:[~2023-07-30 21:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-30 17:32 [Buildroot] [PATCH 1/1] arch/Config.in.x86: add Intel and AMD GCC targets Vincent Fazio
2023-07-30 21:01 ` Thomas Petazzoni via buildroot [this message]
2023-07-30 23:38 ` Vincent Fazio
2023-07-31 19:14 ` [Buildroot] [PATCH v2 " Vincent Fazio
2023-07-31 22:18 ` Thomas Petazzoni via buildroot
2023-07-31 22:33 ` Vincent Fazio
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