Hi, On 2025-03-03 15:50:55 +0000, Pavel Begunkov 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. This is very much appreciated! > 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 FWIW, I'd expect bigger wins with real IO when using 1GB huge pages. I encountered when there were a lot of reads from a large nvme raid into a small set of shared huge pages (database buffer pool), by many proceses concurrently. The constant pinning/unpinning of the relevant folio caused a lot of contention. Unfortunately switching to registered buffers would, until now, have required using non-vectored IO, which causes significant performance regressions in other cases... Greetings, Andres Freund
