Simple question about network stack

[Badalian Vyacheslav <slavon@bigtelecom.ru>]

Hi all.
Sorry for offtopic.
Have problems with balance CPU load in networking.

Have 2 Ethernet adapters e1000. Have 8 CPU (4 real).
Computer work as Shaper. Use only TC rules to shape and IPTABLES to drop.

rx on eth0 go to CPU0. traffic above 400mbs do 90% SI.
rx on eth1 go to CPU1. traffic above 400mbs do 90% SI.
All other CPUS 100%idle.

question:
1. I may balance load to other cpu? I understand that i can't balance
polling place, but find in TC and IPTABLES hash may do different cpu?
2. If SI on 1 cpu more then 100% (600mbs traffic) i see strange. SOFTIRQ
process do 100%. Traffic bandwidth go from 400mbs to 100 mbs. pings
trough computer go from 0.5ms to 100ms. 1 cpu use 100%. All other cpu
100%idle.  If traffic down - after some time cpu load again go to
different cpu.

P.S. Very strange that computer with 4(8) CPU and 1 CPU HT do some
network performance.
P.P.S Sorry for my English

Thanks for answers.
Slavon