On Mon, Dec 04, 2017 at 04:07:15PM -0800, Michael Chan wrote:

As already pointed out, GRO_HW is a subset of GRO.  Packets that
cannot be aggregated in hardware (due to hardware resource limitations
or protocol types that it doesn't handle) can just be passed to the
stack for GRO aggregation.

How would the parameters/limits work in this case? I mean, currently
we have the default weight of 64 packets per napi poll cycle, the
budget of 300 per cycle and also the time constrain,
net.core.netdev_budget_usecs.

With GRO_HW, this 64 limit may be exceeded. I'm looking at qede code
and it works by couting each completion as 1 rcv_pkts
(qede_fp.c:1318). So if it now gets 64 packets, it's up to 64*MTU
aprox, GRO'ed or not. But with GRO_HW, seems it may be much more than
that and which may not be fair with other interfaces in the system.
Drivers supporting GRO_HW probably should account for this.

And how can one control how much time a packet may spend on NIC queue
waiting to be GRO'ed? Does it use the coalescing parameters for that?

  Marcelo