From: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: David Marchand <david.marchand@redhat.com>,
dev@dpdk.org, navasile@linux.microsoft.com,
dmitrym@microsoft.com, pallavi.kadam@intel.com,
Beilei Xing <beilei.xing@intel.com>, Jeff Guo <jia.guo@intel.com>,
Wenzhuo Lu <wenzhuo.lu@intel.com>,
Leyi Rong <leyi.rong@intel.com>,
Bruce Richardson <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH] net/i40e: disable AVX512 for Windows
Date: Wed, 20 Jan 2021 22:27:37 +0300 [thread overview]
Message-ID: <20210120222737.5f1fbd5c@sovereign> (raw)
In-Reply-To: <77c3a7fb-a703-4b8d-62b5-f81dcfcca15a@intel.com>
On Wed, 20 Jan 2021 18:24:43 +0000, Ferruh Yigit wrote:
> On 1/20/2021 6:21 PM, Dmitry Kozlyuk wrote:
> > On Wed, 20 Jan 2021 17:40:16 +0100, David Marchand wrote:
> >> There is probably better to do rather than disabling AVX512 globally for
> >> Windows but since I saw no patch fixing this, here it is.
> >>
> >> ---
> >> drivers/net/i40e/meson.build | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/net/i40e/meson.build b/drivers/net/i40e/meson.build
> >> index c0acdf4fd4..c9a1a50407 100644
> >> --- a/drivers/net/i40e/meson.build
> >> +++ b/drivers/net/i40e/meson.build
> >> @@ -54,7 +54,7 @@ if arch_subdir == 'x86'
> >> cc.has_argument('-mavx512f') and
> >> cc.has_argument('-mavx512bw'))
> >>
> >> - if i40e_avx512_cpu_support == true or i40e_avx512_cc_support == true
> >> + if not is_windows and (i40e_avx512_cpu_support == true or i40e_avx512_cc_support == true)
> >> cflags += ['-DCC_AVX512_SUPPORT']
> >> avx512_args = [cflags, '-mavx512f', '-mavx512bw']
> >> if cc.has_argument('-march=skylake-avx512')
> >
> > Clang doesn't seem to be affected, suggesting a cc.get_id() == 'gcc' check.
> >
> > The error seems related to SEH (structured exception handling). Some MinGW
> > flavours don't use it, which can explain why the bug isn't not 100%
> > reproducible. IMO, just disabling AVX512 for MinGW is enough.
> >
>
> Is there a way to disable it selectively, only for the compiler versions that
> doesn't support it?
It was a guesswork and it proved wrong, setsmp/longjmp flavour [1] with
GCC 8.1.0 also fails. Fedora 32 has GCC 9.2.1 (works), while Fedora 33 has
GCC 10.2.1 (fails). I use a reproducible environment [2] with GCC 9.3.0,
which succeeds. Seems like GCC 9 is the only known version that works, which
is pretty close to "doesn't work with MinGW at all".
[1]:
https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win64/Personal%20Builds/mingw-builds/8.1.0/threads-win32/sjlj/x86_64-8.1.0-release-win32-sjlj-rt_v6-rev0.7z
[2]: https://github.com/PlushBeaver/nix-shells/tree/master/dpdk
prev parent reply other threads:[~2021-01-20 19:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 16:40 David Marchand
2021-01-20 17:46 ` David Marchand
2021-01-20 17:56 ` Ferruh Yigit
2021-01-20 18:21 ` Dmitry Kozlyuk
2021-01-20 18:24 ` Ferruh Yigit
2021-01-20 19:27 ` Dmitry Kozlyuk [this message]
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