On Sun, 2010-08-22 at 22:39 -0700, Tom Herbert wrote:
[...]

Each transmit queue can be associated with a number of CPUs which will
used the queue to send packets.  This is configured as a CPU mask on a
per queue basis in:

/sys/class/net/eth<n>/queues/tx-<n>/xps_cpus

The mappings are stored per device in an inverted data structure that
maps CPUs to queues.  In the netdevice structure this is an array of
num_possible_cpu structures where each array entry contains a bit map
of queues which that CPU can use.

[...]

The mapping of TX queue to CPU should match the affinity of the
completion IRQ for that queue.  It should not be a separate setting.

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.