Re: [RFC PATCH net-next 00/12] XDP batching for TUN/vhost_net

On Mon, May 21, 2018 at 05:04:21PM +0800, Jason Wang wrote:

Hi all:

We do not support XDP batching for TUN since it can only receive one
packet a time from vhost_net. This series tries to remove this
limitation by:

- introduce a TUN specific msg_control that can hold a pointer to an
  array of XDP buffs
- try copy and build XDP buff in vhost_net
- store XDP buffs in an array and submit them once for every N packets
  from vhost_net
- since TUN can only do native XDP for datacopy packet, to simplify
  the logic, split datacopy out logic and only do batching for
  datacopy.

I like how this rework looks. Pls go ahead and repost as
non-RFC.

With this series, TX PPS can improve about 34% from 2.9Mpps to
3.9Mpps when doing xdp_redirect_map between TAP and ixgbe.

Thanks

Jason Wang (12):
  vhost_net: introduce helper to initialize tx iov iter
  vhost_net: introduce vhost_exceeds_weight()
  vhost_net: introduce vhost_has_more_pkts()
  vhost_net: split out datacopy logic
  vhost_net: batch update used ring for datacopy TX
  tuntap: enable premmption early
  tuntap: simplify error handling in tun_build_skb()
  tuntap: tweak on the path of non-xdp case in tun_build_skb()
  tuntap: split out XDP logic
  vhost_net: build xdp buff
  vhost_net: passing raw xdp buff to tun
  vhost_net: batch submitting XDP buffers to underlayer sockets

 drivers/net/tun.c      | 226 +++++++++++++++++++++++++++----------
 drivers/vhost/net.c    | 297 ++++++++++++++++++++++++++++++++++++++++++++-----
 include/linux/if_tun.h |   7 ++
 3 files changed, 444 insertions(+), 86 deletions(-)

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2.7.4