I'm using Debian 9(stretch edition) kernel 4.9., hp dl385 g7 server with 32 cpu cores. NIC queues are tied to processor cores. Server is shaping traffic (iproute2 and htb discipline + skbinfo + ipset + ifb) and filtering some rules by iptables.
At that moment, when traffic goes up about 1gbit/s cpu is very high loaded. Perf tool tells me that kernel module
native_queued_spin_lock_slowpath loading cpu about 40%.
Who knows how to find the problem?