Hi - We currently use mqprio on ifb to work around the qdisc root lock contention on the receiver side. The problem that we found was that queue_mapping is already set when redirecting from ingress qdisc to ifb (based on RX selection, I guess?) so the TX queue selection is not based on priority.
Then we implemented a filter which can set skb->queue_mapping to 0 so that TX queue selection can be done as expected and flows with different priorities will go through different TX queues. However with the queue_mapping recomputed, we found the achievable bandwidth with small packets (512 bytes) dropped significantly if they're targeting different queues. From perf profile I don't see any bottleneck from CPU perspective. Any thoughts on why modifying queue_mapping will have this kind of effect? Also is there any better way of achieving receiver side throttling using HTB while avoiding the qdisc root lock on ifb? Thanks, Michael
