On Fri, 2013-11-08 at 12:24 +0800, Herbert Xu wrote:

I don't know why you're fixing this problem by disabling/degrading
GRO instead of fixing the qdisc to intelligently segment the GRO
packet.

On what criteria you decide that the packet you are going to queue to
the NIC must be segmented ?

How do you predict the future ?

BTW, the Qdisc API doesnt really permit what you describe.

There are the queue() and dequeue(). Once packet is dequeued, you cannot
requeue a bunch of packets if you decide to segment the GRO packet.

This would require a lot of changes, while its much easier to give a
limit to GRO layer (replace the 65536 constant in skb_gro_receive() to
dev->max_gro_size).

Its rare the same host is used both as a latency sensitive router, and a
virt box...