Hi Li,
The assumption of ovs being dependent on dpdk for avx512 might not be true.
I found these two commits below in ovs-2.14.2 which strips out the "-march" and
"-mno-avx512f" flags exported by dpdk i.e removes dependency on DPDK. The
reason for this is rightly mentioned below as well. Hope this helps.
commit bb8f0e2a810889241f1d886d160ccee9b96c4d63
Author: Ian Stokes <ian.sto...@intel.com>
Date: Fri Jan 15 15:46:02 2021 +0000
acinclude: Strip out -mno-avx512f provided by DPDK.
DPDK forces '-mno-avx512f' flag for the application if the toolchain
used to build DPDK had broken AVX512 support.
DPDK forces '-mno-avx512f' flag for the application if the toolchain
used to build DPDK had broken AVX512 support. But OVS could be built
with a completely different or fixed toolchain with correct avx512
support.
Fix that by stripping out `-mno-avx512f` as we already do for '-march'.
This will allow the OVS to decide if the AVX512 can be used.
Reordering of CFLAGS (i.e. adding DPDK flags before OVS ones) is not an
option since autotools might reorder them back later and it's very
unpredictable.
Reported-at: https://github.com/openvswitch/ovs-issues/issues/201
Signed-off-by: Ilya Maximets <i.maxim...@ovn.org>
Co-authored-by: Ilya Maximets <i.maxim...@ovn.org>
Signed-off-by: Ian Stokes <ian.sto...@intel.com>
commit e9f9104d00006a83ce7efd702120171835991779
Author: Ian Stokes <ian.sto...@intel.com>
Date: Fri Jan 15 14:54:04 2021 +0000
acinclude: Strip out -march provided by DPDK.
DPDK flags may include -march. Forcing -march could be
considered too heavy a requirement when users compile OVS from
source and could override user provided options.
Resolve this by stripping -march from provided DPDK flags.
Signed-off-by: Ian Stokes <ian.sto...@intel.com>
Thanks and Regards,
Sunil
> -----Original Message-----
> From: discuss <ovs-discuss-boun...@openvswitch.org> On Behalf Of Li Zhang
> Sent: Thursday, June 2, 2022 6:35 PM
> To: ovs-discuss@openvswitch.org
> Subject: [ovs-discuss] One question about AVX512 support
>
> Hi all,
>
> We are using openvswitch 2.14.2, and dpdk-19.11.4. I found avx512 is
> enabled by default but it's disabled in DPDK. But I think ovs is dependent
> on the dpdk library, right? But why does ovs work with
> avx512 disabled in DPDK?
>
> I am not quite sure about the relationship between OVS and DPDK, any
> suggestions?
>
> --
>
> Best Regards
> -Li
> _______________________________________________
> discuss mailing list
> disc...@openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
_______________________________________________
discuss mailing list
disc...@openvswitch.org
https://mail.openvswitch.org/mailman/listinfo/ovs-discuss
