cxgbe(4):  T4_SET_SCHED_CLASS and T4_SET_SCHED_QUEUE ioctls to program
scheduling classes in the chip and to bind tx queue(s) to a scheduling
class respectively.  These can be used for various kinds of tx traffic
throttling (to force selected tx queues to drain at a fixed Kbps rate,
or a % of the port's total bandwidth, or at a fixed pps rate, etc.).

Obtained from:	Chelsio