Re: [PATCH net-next v4 00/27] io_uring zerocopy send

David Ahern
2022-09-28T19:31:45Z

On 9/26/22 1:08 PM, Pavel Begunkov wrote:
> Tried it out, the branch below fixes a small problem, adds a couple
> of extra optimisations and now it actually uses registered buffers.
>
>     https://github.com/isilence/iperf iou-sendzc

thanks for the patch; will it pull it in.

>
> Still, the submission loop looked a bit weird, i.e. it submits I/O
> to io_uring only when it exhausts sqes instead of sending right
> away with some notion of QD and/or sending in batches. The approach
> is good for batching (SQ size =16 here), but not so for latency.
>
> I also see some CPU cycles being burnt in select(2). io_uring wait
> would be more natural and perhaps more performant, but I didn't
> spend enough time with iperf to say for sure.

ok. It will be a while before I have time to come back to it. In the
meantime it seems like some io_uring changes happened between your dev
branch and what was merged into liburing (compile worked on your branch
but fails with upstream). Is the ZC support in liburing now?