cvs commit: src/sys/net if.h

[Jack Vogel]

On 6/11/07, Andre Oppermann <andre at freebsd.org> wrote:
> Jack Vogel wrote:
> > On 6/11/07, Andre Oppermann <andre at freebsd.org> wrote:
> >> Jack Vogel wrote:
> >> > On 6/11/07, Jack Vogel <jfvogel at gmail.com> wrote:
> >> >> On 6/11/07, Sam Leffler <sam at errno.com> wrote:
> >> >> > Andre Oppermann wrote:
> >> >> > > andre       2007-06-11 20:08:12 UTC
> >> >> > >
> >> >> > >   FreeBSD src repository
> >> >> > >
> >> >> > >   Modified files:
> >> >> > >     sys/net              if.h
> >> >> > >   Log:
> >> >> > >   Add IFCAP_LRO flag for drivers to announce their TCP Large
> >> >> Receive Offload
> >> >> > >   capabilities.
> >> >> > >
> >> >> > >   Revision  Changes    Path
> >> >> > >   1.108     +1 -0      src/sys/net/if.h
> >> >> > > http://cvsweb.FreeBSD.org/src/sys/net/if.h.diff?r1=1.107&r2=1.108
> >> >> > >
> >> >> > >
> >> >> > There are many offload capabilities defined that are not well
> >> thought
> >> >> > out.  In particular we do not distinguish between ipv4 and ipv6 for
> >> >> > things like cksum and tso so there's no way to disable individual
> >> >> > features.  The ability to tweak LRO is clearly needed and clearly
> >> >> belong
> >> >> > as an ifnet capability but unilateraly deciding this is the wrong
> >> >> approach.
> >> >> >
> >> >> >         Sam
> >> >>
> >> >> We do distinguish between TSO4 and TSO6, its just that all the pieces
> >> >> for 6 arent actually there yet, you are right about the cksum
> >> >> granularity,
> >> >> but I'm not convinced its needed. You might be right on the need to
> >> >> fine tune the functionality, but having a big ON/OFF doesnt seem a
> >> >> bad thing to me.
> >> >
> >> > Oh, one other useful tidbit, for Oplin when RSS is enabled you can't do
> >> > CKSUM anyway, they reuse bits.
> >>
> >> What is Oplin?
> >
> > Our new 10G adapter, er, its code name, its really 82598.
>
> OK, then what is this 'RSS' feature?

I think its a windowism, stands for Receive Side Scaling, and what it means
is multiple receive queues, each with an MSI/X vector so they can interrupt
different CPUs, or they can be tied to virtual guests, or MACs, etc etc...

Jack