Re: Modification to skb->queue_mapping affecting performance

On Tue, 2016-09-13 at 17:23 -0700, Michael Ma wrote:

If I understand correctly this is still to associate a qdisc with each
ifb TXQ. How should I do this if I want to use HTB? I guess I'll need
to divide the bandwidth of each class in HTB by the number of TX
queues for each individual HTB qdisc associated?

My original idea was to attach a HTB qdisc for each ifb queue
representing a set of flows not sharing bandwidth with others so that
root lock contention still happens but only affects flows in the same
HTB. Did I understand the root lock contention issue incorrectly for
ifb? I do see some comments in __dev_queue_xmit() about using a
different code path for software devices which bypasses
__dev_xmit_skb(). Does this mean ifb won't go through
__dev_xmit_skb()?

You can install HTB on all of your MQ children for sure.

Again, there is no qdisc lock contention if you properly use MQ.

Now if you _need_ to install a single qdisc for whatever reason, then
maybe you want to use a single rx queue on the NIC, to reduce lock
contention ;)