[PATCH] Mantaining turnstile aligned to 128 bytes in i386 CPUs

[Kip Macy]

> Maybe even someone finds a way to get optimized versions of memcpy in
> the kernel :)
>
> I was thinking: AFAIK the only major stopper is context saving of the
> various "auxiliary" registers - FPU, MMX, SSE, right? But is it an
> all-or-nothing situation? I.e. does it make sense (can it be done?) to
> just elect to save the MMX context? (AFAIK they are different registers
> than SSE, but overlay FPU registers?) The idea is to save something
> smaller than the full set.

It makes a huge difference in a proprietary file serving appliance
that I know of. However, past measurements on FreeBSD have supposedly
indicated that it isn't that big win as a result of increased context
switch time.

     -Kip