kworker high CPU usage in Ubuntu 12.04 [3.6.1-x3] BeagleBoard-xM Rev C

Hello all,

I’m experiencing kworker high CPU usage when transmitting files via Wifi in AP mode.
I have files stored in an external HD and I want to transmit then with vsftpd.
I’m achieving transfers up to 4 Mb/s but I’m observing that they are being limited by kworker/u:1, kworker/u:0 and kworker/u:2.
While vsftp is spending 33% cpu kworkers are spending 66%, so I think kworkers are producing a bottleneck.

Is there any way to reduce kworker cpu ussage while maintaining a good disk / wifi performance?