From: Eric Dumazet <eric.dumazet@gmail.com>
To: Xuan Zhuo <xuanzhuo@linux.alibaba.com>, Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org
Subject: Re: [PATCH net-next] virtio-net: page_to_skb() use build_skb when there's sufficient tailroom
Date: Wed, 7 Apr 2021 19:13:35 +0200 [thread overview]
Message-ID: <84995a39-c588-3aa0-98ff-f16087dbdff0@gmail.com> (raw)
In-Reply-To: <20210407054949.98211-1-xuanzhuo@linux.alibaba.com>
On 4/7/21 7:49 AM, Xuan Zhuo wrote:
> In page_to_skb(), if we have enough tailroom to save skb_shared_info, we
> can use build_skb to create skb directly. No need to alloc for
> additional space. And it can save a 'frags slot', which is very friendly
> to GRO.
>
> Here, if the payload of the received package is too small (less than
> GOOD_COPY_LEN), we still choose to copy it directly to the space got by
> napi_alloc_skb. So we can reuse these pages.
>
> Testing Machine:
> The four queues of the network card are bound to the cpu1.
>
> Test command:
> for ((i=0;i<5;++i)); do sockperf tp --ip 192.168.122.64 -m 1000 -t 150& done
>
> The size of the udp package is 1000, so in the case of this patch, there
> will always be enough tailroom to use build_skb. The sent udp packet
> will be discarded because there is no port to receive it. The irqsoftd
> of the machine is 100%, we observe the received quantity displayed by
> sar -n DEV 1:
>
> no build_skb: 956864.00 rxpck/s
> build_skb: 1158465.00 rxpck/s
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> Suggested-by: Jason Wang <jasowang@redhat.com>
> ---
This will generate merge conflicts.
Please wait that commit 0f6925b3e8da ("virtio_net: Do not pull payload in skb->head") has reached net-next.
Also are we sure pages are always writable, and not shared ?
prev parent reply other threads:[~2021-04-07 17:13 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 5:49 [PATCH net-next] virtio-net: page_to_skb() use build_skb when there's sufficient tailroom Xuan Zhuo
2021-04-07 17:13 ` Eric Dumazet [this message]
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