Results:

    15.96%  [kernel]                      [k] _raw_spin_unlock_irqrestore
    12.81%  [kernel]                      [k] mmiocpy
     6.26%  [kernel]                      [k] __copy_to_user_memcpy
     6.02%  [kernel]                      [k] __local_bh_enable_ip
     5.13%  [igb]                         [k] igb_poll

When it hit full blast, I started getting "Events are being lost, check IO/CPU overload!"