Re: [PATCH 0/8] Add support for vectored registered buffers

[Caleb Sander Mateos <csander@purestorage.com>]

On Mon, Mar 3, 2025 at 7:51 AM Pavel Begunkov <asml.silence@gmail.com> wrote:
>
> Add registered buffer support for vectored io_uring operations. That
> allows to pass an iovec, all entries of which must belong to and
> point into the same registered buffer specified by sqe->buf_index.
>
> The series covers zerocopy sendmsg and reads / writes. Reads and
> writes are implemented as new opcodes, while zerocopy sendmsg
> reuses IORING_RECVSEND_FIXED_BUF for the api.
>
> Results are aligned to what one would expect from registered buffers:
>
> t/io_uring + nullblk, single segment 16K:
>   34 -> 46 GiB/s
> examples/send-zerocopy.c default send size (64KB):
>   82558 -> 123855 MB/s

Thanks for implementing this, it's great to be able to combine these 2
optimizations! Though I suspect many applications will want to perform
vectorized I/O using iovecs that come from different registered
buffers (e.g. separate header and data allocations). Perhaps a future
improvement could allow a list of buffer indices to be specified.

Thanks,
Caleb