Hi Willem, On 3/2/23 16:48, Willem de Bruijn wrote: > From: Willem de Bruijn <willemb@xxxxxxxxxx> > > UDP_SEGMENT was added in commit bec1f6f69736 > ("udp: generate gso with UDP_SEGMENT") > > $ git describe --contains bec1f6f69736 > linux/v4.18-rc1~114^2~377^2~8 > > Kernel source has example code in tools/testing/selftests/net/udpgso* > > Per https://www.kernel.org/doc/man-pages/patches.html, > "Describe how you obtained the information in your patch": > I am the author of the above commit and follow-ons. > > Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx> > It doesn't apply. Can you please rebase on top of master? Thanks, Alex > --- > > Changes v1->v2 > - semantic newlines: also break on comma and colon > - remove bold: section number following function name > - add bold: special macro USHRT_MAX > --- > man7/udp.7 | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > > diff --git a/man7/udp.7 b/man7/udp.7 > index 5822bc551fdf..6646c1e96bb0 100644 > --- a/man7/udp.7 > +++ b/man7/udp.7 > @@ -204,6 +204,34 @@ portable. > .\" UDP_ENCAP_ESPINUDP draft-ietf-ipsec-udp-encaps-06 > .\" UDP_ENCAP_L2TPINUDP rfc2661 > .\" FIXME Document UDP_NO_CHECK6_TX and UDP_NO_CHECK6_RX, added in Linux 3.16 > +.TP > +.BR UDP_SEGMENT " (since Linux 4.18)" > +Enables UDP segmentation offload. > +Segmentation offload reduces > +.BR send (2) > +cost by transferring multiple datagrams worth of data as a single large > +packet through the kernel transmit path, > +even when that exceeds MTU. > +As late as possible, > +the large packet is split by segment size into a series of datagrams. > +This segmentation offload step is deferred to hardware if supported, > +else performed in software. > +This option takes a value between 0 and > +.BR USHRT_MAX > +that sets the segment size: > +the size of datagram payload, > +excluding the UDP header. > +The segment size must be chosen such that at most 64 datagrams are sent in > +a single call and that the datagrams after segmentation meet the same MTU > +rules that apply to datagrams sent without this option. > +Segmentation offload depends on checksum offload, > +as datagram checksums are computed after segmentation. > +The option may also be set for individual > +.BR sendmsg (2) > +calls by passing it as a > +.BR cmsg (7). > +A value of zero disables the feature. > +This option should not be used in code intended to be portable. > .SS Ioctls > These ioctls can be accessed using > .BR ioctl (2).