[.32-rc3] scheduler: iwlagn consistently high in "waiting for CPU"

[Frans Pop <elendil@planet.nl>]

With .32-rc3 I'm getting occasional skips from amarok while playing music 
from an NFS share (3 today so far), something I've not had in a long time.

The reason looks to be that latencytop consistently shows 'iwlagn' as the 
top affected process with "Scheduler: waiting for CPU".
Values of 100-140 ms occur frequently, but I've also seen higher values 
(180, 207). I don't remember seeing iwlagn high in the list before, but I 
have not checked earlier kernels yet.

Added to that 'phy0' also frequently shows high with values of 25-75 ms.

The system is otherwise essentially idle. Other processes typically show a 
latency < 5 ms.

System: HP 2510p notebook, x86_64, Core2 Duo, Debian stable

Cheers,
FJP