> -----Original Message----- > From: William Tu <u9012...@gmail.com> > Sent: Tuesday, June 16, 2020 4:41 PM > To: Van Haaren, Harry <harry.van.haa...@intel.com> > Cc: ovs-dev <ovs-dev@openvswitch.org>; Stokes, Ian <ian.sto...@intel.com>; > Ilya Maximets <i.maxim...@ovn.org>; Federico Iezzi <fie...@redhat.com> > Subject: Re: [PATCH v3 6/7] dpif-lookup: add avx512 gather implementation > > On Wed, Jun 10, 2020 at 3:47 AM Harry van Haaren > <harry.van.haa...@intel.com> wrote: <snip body of commit msg> > > v3: > > - Improve function name for _any subtable lookup > > - Use "" include not <> for immintrin.h > > - Add checks for SSE42 instructions in core OVS for CRC32 based hashing > > If not available, disable AVX512 lookup implementation as it requires > > uses CRC32 for hashing, and the hashing algorithm must match core OVS. > > Issue a #warning when building x86_64 without SSE42 for core OVS. > > Where did you add this warning?
Initially I did (and added it to commit message), but removed it later as it was failing some builds (but never removed it from commit message!). Will remove from commit message. <snip code/commit details> > > +# Build lookupavx512 library with extra CFLAGS enabled. This allows the > > +# compiler to use the ISA features required for the ISA optimized > > code-paths. > > +lib_libopenvswitchlookupavx512_la_CFLAGS = \ > > + -mavx512f \ > > + -mavx512bw \ > > + -mavx512dq \ > > + -mbmi2 \ > > + $(AM_CFLAGS) > > +lib_libopenvswitchlookupavx512_la_SOURCES = \ > > + lib/dpif-netdev-lookup-avx512-gather.c > > + > the robot is showing error > gcc: error: unrecognized command line option '-mavx512f' > looks like the older version of gcc doesn't have the option. > I don't know a better way to check gcc flags support, maybe add > a check at acinclude.m4, the _OVS_CHECK_CC_OPTION? Yes correct - older GCC versions (before 4.9) don't have a -mavx512f or other AVX512 related flags. I've added a CHECK_CC_OPTION around the AVX512 code in the v4, just as suggested. Unfortunately it results in an #ifdef around some code, but this the best solution I think. Thanks for review, -Harry <snip> _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev
