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Date:   Wed, 17 Feb 2021 22:08:55 -0800
From:   John Fastabend <john.fastabend@gmail.com>
To:     Alexander Lobakin <alobakin@pm.me>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Magnus Karlsson <magnus.karlsson@intel.com>
Cc:     "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Jonathan Lemon <jonathan.lemon@gmail.com>,
        Alexei Starovoitov <ast@kernel.org>,
        =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>,
        Jesper Dangaard Brouer <hawk@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        KP Singh <kpsingh@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
        Eric Dumazet <eric.dumazet@gmail.com>,
        Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
        Dust Li <dust.li@linux.alibaba.com>,
        Alexander Lobakin <alobakin@pm.me>,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, bpf@vger.kernel.org
Message-ID: <602e0477af4c2_1f0ef2088e@john-XPS-13-9370.notmuch>
In-Reply-To: <20210217120003.7938-1-alobakin@pm.me>
References: <20210217120003.7938-1-alobakin@pm.me>
Subject: RE: [PATCH v7 bpf-next 0/6] xsk: build skb by page (aka generic
 zerocopy xmit)
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Alexander Lobakin wrote:
> This series introduces XSK generic zerocopy xmit by adding XSK umem
> pages as skb frags instead of copying data to linear space.
> The only requirement for this for drivers is to be able to xmit skbs
> with skb_headlen(skb) == 0, i.e. all data including hard headers
> starts from frag 0.
> To indicate whether a particular driver supports this, a new netdev
> priv flag, IFF_TX_SKB_NO_LINEAR, is added (and declared in virtio_net
> as it's already capable of doing it). So consider implementing this
> in your drivers to greatly speed-up generic XSK xmit.

[...]
 
> ---------------- Performance Testing ------------
> 
> The test environment is Aliyun ECS server.
> Test cmd:
> ```
> xdpsock -i eth0 -t  -S -s <msg size>
> ```
> 
> Test result data:
> 
> size    64      512     1024    1500
> copy    1916747 1775988 1600203 1440054
> page    1974058 1953655 1945463 1904478
> percent 3.0%    10.0%   21.58%  32.3%
> 

For the series, but might be good to get Dave or Jakub to check
2/6 to be sure they agree.

Acked-by: John Fastabend <john.fastabend@gmail.com>