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From: Bruce Richardson <bruce.richardson@intel.com>
To: Liang Ma <liangma@liangbit.com>
Cc: dev@dpdk.org, leyi.rong@intel.com,
	Liang Ma <liangma@bytedance.com>,
	stable@dpdk.org,
	Konstantin Ananyev <konstantin.ananyev@intel.com>
Subject: Re: [dpdk-dev] [PATCH v3] build: check AVX512 rather than compiler version
Date: Tue, 20 Jul 2021 12:58:13 +0100	[thread overview]
Message-ID: <YPa6VWZKPs9kq1Uo@bricha3-MOBL.ger.corp.intel.com> (raw)
In-Reply-To: <20210720112059.2547-1-liangma@liangbit.com>

On Tue, Jul 20, 2021 at 12:20:59PM +0100, Liang Ma wrote:
> From: Liang Ma <liangma@bytedance.com>
> 
> GCC 6.3.0 has a known bug which related to _mm512_extracti64x4_epi64.
> Please reference https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82887
> 
> Some DPDK PMD avx512 version heavily use _mm512_extracti64x4_epi6,
> which cause building failure with debug buildtype.
> 
> Therefore, it's helpful to check if compiler work with
> _mm512_extracti64x4_epi6.
> 
> This patch check the compiler compile result against the test code
> snippet. If the checking is failed then disable avx512.
> 
> Bugzilla ID: 717
> Fixes: e6a6a138919f (net/i40e: add AVX512 vector path)
> Fixes: 808a17b3c1e6 (net/ice: add Rx AVX512 offload path)
> Fixes: 4b64ccb328c9 (net/iavf: fix VLAN extraction in AVX512 path)
> Cc: stable@dpdk.org
> 
> Reported-by: Liang Ma <liangma@liangbit.com>
> Signed-off-by: Liang Ma <liangma@bytedance.com>
> ---

One minor comment below. Also the commit title needs rewording, since the
current title is based on the changes from V1->V2 of your patch. I'd
suggest something like:
"build: check for broken AVX-512 compiler support"

With fixed title:
Acked-by: Bruce richardson <bruce.richardson@intel.com>

>  config/x86/meson.build | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/config/x86/meson.build b/config/x86/meson.build
> index b9348c44de..87b051cd2d 100644
> --- a/config/x86/meson.build
> +++ b/config/x86/meson.build
> @@ -10,6 +10,19 @@ if not is_windows
>      endif
>  endif
>  
> +#check if compiler is working with _mm512_extracti64x4_epi64
> +#Ref https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82887
> +if cc.has_argument('-mavx512f')
> +    code = '''#include <immintrin.h>
> +    void test(__m512i zmm){
> +        __m256i ymm = _mm512_extracti64x4_epi64(zmm, 0);}'''
> +    result = cc.compiles(code, args : '-mavx512f', name : 'avx512 checking')
> +    if result == false

You can get rid of the "result" variable and just do
	if not cc.compiles(...)
It might be a little more readable.

> +        machine_args += '-mno-avx512f'
> +        warning('Broken _mm512_extracti64x4_epi64, disabling AVX512 support')
> +    endif
> +endif
> +
>  # we require SSE4.2 for DPDK
>  if cc.get_define('__SSE4_2__', args: machine_args) == ''
>      message('SSE 4.2 not enabled by default, explicitly enabling')
> -- 
> 2.17.1
> 

  reply	other threads:[~2021-07-20 11:58 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-17 17:08 [dpdk-dev] [PATCH] buildtools: Check GCC version to avoid GCC 6.3.0 avx512 bug Liang Ma
2021-07-17 17:48 ` Stephen Hemminger
2021-07-17 22:13   ` Liang Ma
2021-07-18  1:08     ` Stephen Hemminger
2021-07-18  9:33       ` Liang Ma
2021-07-19  8:38         ` Bruce Richardson
2021-07-19 10:04           ` Liang Ma
2021-07-19 22:34 ` [dpdk-dev] [PATCH v2] build: check AVX512 rather than compiler version Liang Ma
2021-07-20 10:19   ` Bruce Richardson
2021-07-20 11:24     ` Liang Ma
2021-07-20 11:20 ` [dpdk-dev] [PATCH v3] " Liang Ma
2021-07-20 11:58   ` Bruce Richardson [this message]
2021-07-20 13:25     ` Liang Ma
2021-07-20 13:36 ` [dpdk-dev] [PATCH v4] build: check for broken AVX-512 compiler support Liang Ma
2021-07-22 17:58   ` [dpdk-dev] [dpdk-stable] " Thomas Monjalon

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