Re: [PATCH for-next 0/3] io_uring: multishot recvmsg

[Paolo Abeni <pabeni@redhat.com>]

On Fri, 2022-07-08 at 11:43 -0700, Dylan Yudaken wrote:
> This series adds multishot support to recvmsg in io_uring.
> 
> The idea is that you submit a single multishot recvmsg and then receive
> completions as and when data arrives. For recvmsg each completion also has
> control data, and this is necessarily included in the same buffer as the
> payload.
> 
> In order to do this a new structure is used: io_uring_recvmsg_out. This
> specifies the length written of the name, control and payload. As well as
> including the flags.
> The layout of the buffer is <header><name><control><payload> where the
> lengths are those specified in the original msghdr used to issue the recvmsg.
> 
> I suspect this API will be the most contentious part of this series and would
> appreciate any comments on it.
> 
> For completeness I considered having the original struct msghdr as the header,
> but size wise it is much bigger (72 bytes including an iovec vs 16 bytes here).
> Testing also showed a 1% slowdown in terms of QPS.
> 
> Using a mini network tester [1] shows 14% QPS improvment using this API, however
> this is likely to go down to ~8% with the latest allocation cache added by Jens.
> 
> I have based this on this other patch series [2].
> 
> [1]: https://github.com/DylanZA/netbench/tree/main
> [2]: https://lore.kernel.org/io-uring/20220708181838.1495428-1-dylany@fb.com/
> 
> Dylan Yudaken (3):
>   net: copy from user before calling __copy_msghdr
>   net: copy from user before calling __get_compat_msghdr
>   io_uring: support multishot in recvmsg
> 
>  include/linux/socket.h        |   7 +-
>  include/net/compat.h          |   5 +-
>  include/uapi/linux/io_uring.h |   7 ++
>  io_uring/net.c                | 195 ++++++++++++++++++++++++++++------
>  io_uring/net.h                |   5 +
>  net/compat.c                  |  39 +++----
>  net/socket.c                  |  37 +++----
>  7 files changed, 215 insertions(+), 80 deletions(-)
> 
> 
> base-commit: 9802dee74e7f30ab52dc5f346373185cd860afab

I read the above as this series is targeting Jens's tree. It looks like
it should be conflicts-free vs net-next.

For the network bits:

Acked-by: Paolo Abeni <pabeni@redhat.com>

Cheers,

Paolo