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From:   Coco Li <lixiaoyan@google.com>
Date:   Tue, 29 Nov 2022 09:29:22 -0800
Message-ID: <CADjXwjhii7fn5yxh78XXfzFinvoxkdBu7F8kwiWTdtOOMeuExw@mail.gmail.com>
Subject: Re: [RFC net-next v2 2/2] bnxt: Use generic HBH removal helper in tx path
To:     Michael Chan <michael.chan@broadcom.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>,
        David Ahern <dsahern@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Andrew Gospodarek <gospo@broadcom.com>
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Great, thanks Michael! Will send a new version of the patch.

Best,
Coco Li


On Tue, Nov 29, 2022 at 12:59 AM Michael Chan <michael.chan@broadcom.com> wrote:
>
> On Wed, Nov 23, 2022 at 11:42 AM Michael Chan <michael.chan@broadcom.com> wrote:
> >
> > On Wed, Nov 23, 2022 at 11:16 AM Coco Li <lixiaoyan@google.com> wrote:
> > >
> > > Eric Dumazet implemented Big TCP that allowed bigger TSO/GRO packet sizes
> > > for IPv6 traffic. See patch series:
> > > 'commit 89527be8d8d6 ("net: add IFLA_TSO_{MAX_SIZE|SEGS} attributes")'
> > >
> > > This reduces the number of packets traversing the networking stack and
> > > should usually improves performance. However, it also inserts a
> > > temporary Hop-by-hop IPv6 extension header.
> > >
> > > Using the HBH header removal method in the previous path, the extra header
> > > be removed in bnxt drivers to allow it to send big TCP packets (bigger
> > > TSO packets) as well.
> > >
> > > Tested:
> > > Compiled locally
> > >
> > > To further test functional correctness, update the GSO/GRO limit on the
> > > physical NIC:
> > >
> > > ip link set eth0 gso_max_size 181000
> > > ip link set eth0 gro_max_size 181000
> > >
> > > Note that if there are bonding or ipvan devices on top of the physical
> > > NIC, their GSO sizes need to be updated as well.
> > >
> > > Then, IPv6/TCP packets with sizes larger than 64k can be observed.
> > >
> > > Signed-off-by: Coco Li <lixiaoyan@google.com>
>
> I've confirmed with our hardware team that this is supported by our
> chips, and I've tested it up to gso_max_size of 524280.  Thanks.
>
> Tested-by: Michael Chan <michael.chan@broadcom.com>
> Reviewed-by: Michael Chan <michael.chan@broadcom.com>