Re: [CFT][PATCH] 2.5.47 Athlon/Druon, much faster copy_user function

[Andi Kleen]

You don't seem to save/restore the FPU state, so it will be likely 
corrupted after your copy runs.

Also I'm pretty sure that using movntq (= forcing destination out of 
cache) is not a good strategy for generic copy_from_user(). It may 
be a win for the copies in write ( user space -> page cache ), but 
will hurt for all the ioctls and other things that actually need the
data in cache afterwards. I am afraid it is not enough to do micro benchmarks
here.

-Andi