On Wed, Sep 15, 2021 at 11:32 AM John Baldwin <j...@freebsd.org> wrote:
> On 9/15/21 8:47 AM, Alan Somers wrote: > > On Wed, Sep 15, 2021 at 9:21 AM John Baldwin <j...@freebsd.org> wrote: > > > >> On 9/14/21 1:53 PM, Alan Somers wrote: > >>> On Tue, Sep 14, 2021 at 2:46 PM John Baldwin <j...@freebsd.org> wrote: > >>> > >>>> The branch main has been updated by jhb: > >>>> > >>>> URL: > >>>> > >> > https://cgit.FreeBSD.org/src/commit/?id=1ecbc1d8e9d3fbcd8e68fc68f0a32944a12ddb1e > >>>> > >>>> commit 1ecbc1d8e9d3fbcd8e68fc68f0a32944a12ddb1e > >>>> Author: John Baldwin <j...@freebsd.org> > >>>> AuthorDate: 2021-09-14 20:46:14 +0000 > >>>> Commit: John Baldwin <j...@freebsd.org> > >>>> CommitDate: 2021-09-14 20:46:14 +0000 > >>>> > >>>> cxgbe tom: Don't queue AIO requests on listen sockets. > >>>> > >>>> This is similar to the fixes in 141fe2dceeae. One difference is > >> that > >>>> TOE sockets do not change states (listen vs non-listen) once > >> created, > >>>> so no lock is needed for SOLISTENING(). > >>>> > >>>> Sponsored by: Chelsio Communications > >>>> > >>> > >>> I've always wondered: what's the point to using AIO with sockets? > Can't > >>> everything socket-related be done better with non-blocking read/write > and > >>> kqueue? > >> > >> Zero-copy operation with TOE is why TOE uses AIO. Zero-copy of user > >> buffers > >> can't really work with the non-AIO APIs because the user buffer is free > to > >> be reused immediately after write(2) (and on the read side you don't > know > >> the buffer in advance to allow the NIC to write directly into the use > >> buffer). > >> > >> In theory we could support zero-copy using mb_ext_pgs for aio_write() > for > >> the non-TOE case similar to what sendfile() does. > >> > >> -- > >> John Baldwin > >> > > > > Interesting. Do you know of any common applications that include this > > optimization? I've been working on the AIO ecosystem for Rust. It would > > be good to ensure that this use case works, especially if zero-copy ever > > works for non-TOE. > > I do not, and I rely on patches I merged upstream to netperf (-a and -A > flags) > to test it. I believe there might be some proprietary bits in some FreeBSD > downstreams that might make use of this. > > -- > John Baldwin > Do you mean these -a and -A flags, or am I looking in the wrong place? -a sizespec Alter the send and receive buffer alignments on the local system. This defaults to 8 bytes. -A sizespec As -a, but for the remote system. _______________________________________________ dev-commits-src-main@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/dev-commits-src-main To unsubscribe, send any mail to "dev-commits-src-main-unsubscr...@freebsd.org"
