On Sat, 16 Nov 2002 11:56:52 +0100
Andi Kleen <ak@suse.de> mentioned:
>
> You don't seem to save/restore the FPU state, so it will be likely
> corrupted after your copy runs.
This is the main question for me that I was wondering for all week.
My first version was using fsave and frstore, so
just changing three lines will accomplish this.
Is it all I need? Any thing elase needed to consider using fpu register?
>
> 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 ),
Yes, that why I included postfetch in the code because movntq does not leave
them in the L2 cache.
Anygood idea to
> 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.
check above?
>
>
> -Andi
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