On Mon, 2015-05-25 at 16:05 -0400, John A. Sullivan III wrote: > Hello, all. One one of our connections we are doing intensive traffic > shaping with tc. We are using ifb interfaces for shaping ingress > traffic and we also use ifb interfaces for egress so that we can apply > the same set of rules to multiple interfaces (e.g., tun and eth > interfaces operating on the same physical interface). > > These are running on very powerful gateways; I have watched them > handling 16 Gbps with CPU utilization at a handful of percent. Yet, I > am seeing drops on the ifb interfaces when I do a tc -s qdisc show. > > Why would this be? I would expect if there was some kind of problem that > it would manifest as drops on the physical interfaces and not the IFB > interface. We have played with queue lengths in both directions. We > are using HFSC with SFQ leaves so I would imagine this overrides the > very short qlen on the IFB interfaces (32). These are drops and not > overlimits.
IFB is single threaded and a serious bottleneck. Don't use this on egress, this destroys multiqueue capaility. And SFQ is pretty limited (127 packets) You might try to change your NIC to have a single queue for RX, so that you have a single cpu feeding your IFB queue. (ethtool -L eth0 rx 1) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
