Bug#692957: linux-image-3.2.0-4-amd64: NFS server causes high load on 3.2 kernel

[Karsten Suehring <suehringbugs@gmail.com>]

Can you also measure the speed at which the client can write, when the
server is running each of the two kernel versions?  If the client can
write twice as fast (for example) then it should be OK to use twice as
high a percentage of CPU time on the server, as the total CPU time
needed for a data transfer will be the same.

I tested the following combinations with 2 GB writes: 

Server                                   Client
Debian testing kernel 2.6        Debian stable     ~60 seconds
Debian testing kernel 3.2        Debian stable     ~60 seconds

Debian testing kernel 2.6        Ubuntu 12.04.1  ~65 seconds
Debian testing kernel 3.2        Ubuntu 12.04.1  ~67 seconds

It seems the speed is comparable in all cases although the load differs. In general my load number looked a bit smaller this time, maybe because the host system was freshly booted. So I guess, I should collect some numbers on an actual machine tomorrow. I also did not have a Debian testing client yet.

Do you know if the patch mentioned above also affect the client?

--Karsten