Comment 6 for bug 1490788

While stopping to send Unknown unicast, ksoftirqd and kworker occupied CPU.

Tasks: 340 total, 9 running, 331 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.0 us, 0.0 sy, 0.0 ni, 23.2 id, 0.0 wa, 0.0 hi, 76.8 si, 0.0 st
KiB Mem: 13168126+total, 4836636 used, 12684462+free, 154340 buffers
KiB Swap: 13413273+total, 0 used, 13413273+free. 592932 cached Mem

   PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
   263 root 20 0 0 0 0 R 66.8 0.0 28:07.37 ksoftirqd/3
   258 root 20 0 0 0 0 R 66.5 0.0 28:08.08 ksoftirqd/2
   253 root 20 0 0 0 0 R 66.2 0.0 28:20.01 ksoftirqd/1
   299 root 20 0 0 0 0 R 33.6 0.0 14:31.11 kworker/1:1
   300 root 20 0 0 0 0 R 33.2 0.0 14:25.87 kworker/2:1
   301 root 20 0 0 0 0 S 33.2 0.0 15:08.83 kworker/3:1
     3 root 20 0 0 0 0 R 0.3 0.0 0:12.34 ksoftirqd/0
  5961 root 20 0 25088 1860 1172 R 0.3 0.0 0:00.06 top
 57022 root 20 0 1224500 863744 46208 S 0.3 0.7 37:23.54 contrail-vroute