Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll()

Hiro Yoshioka
2005-08-25T04:59:00Z

From: Andi Kleen <ak@suse.de>
> > Hi,
> >
> > The following patch does not use MMX regsiters so that we don't have
> > to worry about save/restore the FPU/MMX states.
> >
> > What do you think?
>
> Performance will probably be bad on K7 Athlons - those have a microcoded
> movnti which is quite slow.
>
> Also BTW I don't see any code anywhere that tests the CPUID bits,
> so your code will fail spectacularly on a PII that didn't do SSE
> (intel user copy used to be enabled on those)
>
> One way to solve this might be to use different code using
> alternative()
>
> -Andi

Thanks for your comments. I'll consider it.

Regards,
Hiro