Re: allowing msg_name and msg_control

[Pavel Begunkov <asml.silence@gmail.com>]

On 07/11/2020 14:22, Victor Stewart wrote:
> RE Jen's proposed patch here
> https://lore.kernel.org/io-uring/45d7558a-d0c8-4d3f-c63a-33fd2fb073a5@kernel.dk/

Hmm, I haven't seen this thread, thanks for bringing it up

> 
> and RE what Stefan just mentioned in the "[PATCH 5.11] io_uring: don't
> take fs for recvmsg/sendmsg" thread a few minutes ago... "Can't we
> better remove these checks and allow msg_control? For me it's a
> limitation that I would like to be removed."... which I coincidentally
> just read when coming on here to advocate the same.
> 
> I also require this for a few vital performance use cases:
> 
> 1) GSO (UDP_SEGMENT to sendmsg)
> 2) GRO (UDP_GRO from recvmsg)

Don't know these you listed, may read about them later, but wouldn't [1]
be enough? I was told it's queued up.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/net/socket.c?id=583bbf0624dfd8fc45f1049be1d4980be59451ff

> 
> GSO and GRO are super important for QUIC servers... essentially
> bringing a 3-4x performance improvement that brings them in line with
> TCP efficiency.
> 
> Would also allow the usage of...
> 
> 3) MSG_ZEROCOPY (to receive the sock_extended_err from recvmsg)
> 
> it's only a single digit % performance gain for large sends (but a
> minor crutch until we get registered buffer sendmsg / recvmsg, which I
> plan on implementing).
> 
> So if there's an agreed upon plan on action I can take charge of all
> the work and get this done ASAP.
> 
> #Victor
> 

-- 
Pavel Begunkov