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From: Jason Wang <jasowang@redhat.com>
To: prashantbhole.linux@gmail.com,
	"Michael S . Tsirkin" <mst@redhat.com>,
	"David S . Miller" <davem@davemloft.net>
Cc: David Ahern <dsahern@gmail.com>,
	kvm@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH net-next 0/3] vhost_net: access ptr ring using tap recvmsg
Date: Sat, 12 Oct 2019 15:57:21 +0800
Message-ID: <8f319697-34e1-fde5-65f3-7db8dc723982@redhat.com> (raw)
In-Reply-To: <20191012015357.1775-1-prashantbhole.linux@gmail.com>


On 2019/10/12 上午9:53, prashantbhole.linux@gmail.com wrote:
> From: Prashant Bhole <prashantbhole.linux@gmail.com>
>
> vhost_net needs to peek tun packet sizes to allocate virtio buffers.
> Currently it directly accesses tap ptr ring to do it. Jason Wang
> suggested to achieve this using msghdr->msg_control and modifying the
> behavior of tap recvmsg.


Note this may use more indirect calls, this could be optimized in the 
future by doing XDP/skb receiving by vhost_net its own.


>
> This change will be useful in future in case of virtio-net XDP
> offload. Where packets will be XDP processed in tap recvmsg and vhost
> will see only non XDP_DROP'ed packets.
>
> Patch 1: reorganizes the tun_msg_ctl so that it can be extended by
>   the means of different commands. tap sendmsg recvmsg will behave
>   according to commands.
>
> Patch 2: modifies recvmsg implementation to produce packet pointers.
>   vhost_net uses recvmsg API instead of ptr_ring_consume().
>
> Patch 3: removes ptr ring usage in vhost and functions those export
>   ptr ring from tun/tap.
>
> Prashant Bhole (3):
>    tuntap: reorganize tun_msg_ctl usage
>    vhost_net: user tap recvmsg api to access ptr ring
>    tuntap: remove usage of ptr ring in vhost_net
>
>   drivers/net/tap.c      | 44 ++++++++++++++---------
>   drivers/net/tun.c      | 45 +++++++++++++++---------
>   drivers/vhost/net.c    | 79 ++++++++++++++++++++++--------------------
>   include/linux/if_tun.h |  9 +++--
>   4 files changed, 103 insertions(+), 74 deletions(-)


It would be helpful that if you can share some performance numbers here.

Thanks


  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-12  1:53 prashantbhole.linux
2019-10-12  1:53 ` [PATCH net-next 1/3] tuntap: reorganize tun_msg_ctl usage prashantbhole.linux
2019-10-12  7:44   ` Jason Wang
2019-10-15  0:33     ` Prashant Bhole
2019-10-12  1:53 ` [PATCH net-next 2/3] vhost_net: user tap recvmsg api to access ptr ring prashantbhole.linux
2019-10-12  7:54   ` Jason Wang
2019-10-12 20:41   ` Michael S. Tsirkin
2019-10-15  0:57     ` Prashant Bhole
2019-10-12  1:53 ` [PATCH net-next 3/3] tuntap: remove usage of ptr ring in vhost_net prashantbhole.linux
2019-10-12  7:57 ` Jason Wang [this message]
2019-10-12 20:38   ` [PATCH net-next 0/3] vhost_net: access ptr ring using tap recvmsg Michael S. Tsirkin

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