> I use linux as GiGE router and have 6 NIC on it > Those days the NIC interrupt takes around 100% CPU but the system is 4G memroy and 8 CPU. I can't see any error packet in this NIC interface too > > After I block the udp, the %CPU drops. but the UDP only takes around 8M in general > > We use UDP traffic for voice. > > Do you have any suggestion ? increase the kernel parameter? Add the following lines to /etc/sysctl.conf net.core.rmem_default = 67108864 net.core.wmem_default = 67108864 net.core.rmem_max = 67108864 net.core.wmem_max = 67108864 net.ipv4.tcp_mem = 4096 67108864 67108864 net.ipv4.tcp_rmem = 4096 67108864 67108864 net.ipv4.tcp_wmem = 4096 67108864 67108864 net.ipv4.ip_local_port_range = 32768 65535 net.ipv4.tcp_max_syn_backlog = 8192 After adding these lines, run "sysctl -p"