What does adapter->stats.mpc[] report for ixgbe?

[Jack Vogel]

On Mon, May 7, 2012 at 5:31 PM, Juli Mallett <jmallett at freebsd.org> wrote:

> While we're on the subject, I've had some confusion for some time now:
>
> On Mon, May 7, 2012 at 5:25 PM, Jack Vogel <jfvogel at gmail.com> wrote:
> > Packets are missed when the receive FIFO has insufficient space to store
> the
> > incoming packet.
>
> This means the on-card FIFO, i.e. the fixed-size FIFO that is divided
> into receive and transmit space by the driver, right?  And the
> separate "receive no buffers" counter records instances where the
> packet made it to the card but there was no buffer associated with a
> receive descriptor to write it to?  That has been my interpretation of
> the documentation and the numbers I've seen in practice, but I've seen
> conflicting interpretations and would much rather hear it from the
> horse's mouth :)
>
> Thanks,
> Juli.
>

Gee, not sure if I like being called a horse :)

But yes you are correct. When you have multiple traffic classes, as
it is when you have DCB, then the packet buffer may be partitioned into
up to 8 parts.  This would let you seperate say FCOE and iSCSI from
normal net traffic. But for now in FreeBSD its just one which is divided
into 3 parts: TX, RX, and FDIR (flow director).

Cheers,

Jack