When I was testing with my iPerf changes, I realized that the sch_fq pacing
(which in iperf is set via setsockopt()), is pacing at a bandwidth that's
set at a pretty low level in the stack (which makes sense).  This is
different from the application pacing that iperf does (which is pacing the
goodput).

But it's not clear to me where the X bps determination is being made.  My
current guess is that it's at the interface level (since that's where
sch_fq is), and so it's approximately "bytes on the wire", minus preambles
and inter-packet spacing, and whatnot.  And so it's including all the 802.x
headers involved (vlan tags, qos tags, source/dest macs, etc).  Is this
correct?

-Aaron