[dpdk-dev] [PATCH] buildtools: Check GCC version to avoid GCC 6.3.0 avx512 bug

Liang Ma liangma at liangbit.com
Sun Jul 18 11:33:15 CEST 2021


On Sat, Jul 17, 2021 at 06:08:04PM -0700, Stephen Hemminger wrote:
> On Sat, 17 Jul 2021 23:13:04 +0100
> Liang Ma <liangma at liangbit.com> wrote:
> 
> > On Sat, Jul 17, 2021 at 10:48:49AM -0700, Stephen Hemminger wrote:
> > > On Sat, 17 Jul 2021 18:08:30 +0100
> > > Liang Ma <liangma at liangbit.com> wrote:
> > >   
> > > > From: Liang Ma <liangma at 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 casue building failure with debug buildtype.
> > > > 
> > > > Therefore, it's helpful to disable avx512 for GCC 6.3.0
> > > > 
> > > > 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 at dpdk.org
> > > > 
> > > > Reported-by: Liang Ma <liangma at liangbit.com>
> > > > Signed-off-by: Liang Ma <liangma at bytedance.com>  
> > > 
> > > What distro still has GCC 6.3.0?  
> > For example  Debian 9.x
> 
> Ok, thanks. Is there a bug fix in Debian LTS yet?
I look into  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82887, and
find gcc community has no plan to backport fix. Hence, I don't think
Debian LTS will have any fix for this. That's why I send out this patch.



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