From: "Michael S. Tsirkin" <mst@redhat.com>
To: Heng Qi <hengqi@linux.alibaba.com>
Cc: virtio-dev@lists.oasis-open.org, Jason Wang <jasowang@redhat.com>,
xuanzhuo@linux.alibaba.com, kangjie.xu@linux.alibaba.com
Subject: [virtio-dev] Re: [PATCH v7] virtio_net: support split header
Date: Sun, 4 Sep 2022 16:31:59 -0400 [thread overview]
Message-ID: <20220904162809-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <94937aaa-e3c0-74fe-290c-59884c6eb9a4@linux.alibaba.com>
On Fri, Sep 02, 2022 at 04:58:16PM +0800, Heng Qi wrote:
> When VIRTIO_NET_F_SPLIT_TRANSPORT_HEADER is negotiated,
> the driver requires that the buffers submitted to receiveq
> MUST be composed of at least two descriptors,
> which means that each buffer the device gets is a descriptor chain,
> even if the device does not split the header for some packets.
>
> To store packet in the descriptor chain without header splitting
> by the device, the device MUST start with the first descriptor of
> the descriptor chain to store the packet, and MUST NOT set the
> VIRTIO_NET_HDR_F_SPLIT_TRANSPORT_HEADER bit in \field{flags}.
>
> Thanks.
Descriptor chains will hurt performance badly.
How about simply making this feature depend on mergeable buffers?
Then we have a separate buffer for the header and
this works cleanly.
--
MST
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next prev parent reply other threads:[~2022-09-04 20:32 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-16 9:34 [virtio-dev] [PATCH v7] virtio_net: support split header Heng Qi
2022-08-25 14:22 ` Cornelia Huck
2022-08-30 11:23 ` Heng Qi
2022-08-30 11:26 ` Heng Qi
2022-09-02 4:12 ` Heng Qi
2022-09-08 21:18 ` Michael S. Tsirkin
2022-09-02 6:21 ` [virtio-dev] " Jason Wang
2022-09-02 6:41 ` Michael S. Tsirkin
2022-09-02 8:58 ` Heng Qi
2022-09-04 20:31 ` Michael S. Tsirkin [this message]
2022-09-05 7:52 ` Xuan Zhuo
2022-09-05 8:37 ` Heng Qi
2022-09-05 9:43 ` Xuan Zhuo
2022-09-06 5:47 ` Jason Wang
2022-09-08 21:18 ` Michael S. Tsirkin
2022-09-02 7:36 ` Heng Qi
2022-09-04 20:27 ` Michael S. Tsirkin
2022-09-06 5:56 ` Jason Wang
2022-09-09 7:41 ` [virtio-dev] " Heng Qi
2022-09-09 11:15 ` Michael S. Tsirkin
2022-09-09 12:38 ` Xuan Zhuo
2022-09-14 3:34 ` Jason Wang
2022-09-27 21:35 ` Michael S. Tsirkin
2022-09-28 2:15 ` Heng Qi
2022-09-28 8:01 ` Xuan Zhuo
2022-09-09 12:47 ` Xuan Zhuo
2022-09-13 7:20 ` Heng Qi
2022-09-09 10:22 ` Heng Qi
2022-09-02 8:26 ` Heng Qi
2022-09-06 5:53 ` Jason Wang
2022-09-02 6:48 ` Michael S. Tsirkin
2022-09-07 11:16 ` [virtio-dev] " Heng Qi
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