I_686 MMX / 3DNOW / SSE / SSE2 ?

[Alexander Leidinger]

Quoting Ivan Voras <ivoras at fer.hr> (Mon, 08 May 2006 18:55:48 +0200):

> Alexander Leidinger wrote:
> 
> > The patches which port the revamped FPU handling from DFly don't have
> > this expensive behavior for every switch. AFAIR only when the kernel
> > used the FPU some context is saved. It also allows to use SIMD
> > instructions in the kernel (this may be beneficial in some places).
> 
> For what it's worth - it would be interesting to see if XOR calculations 
> in GRAID3 or VINUM can be speeded up by using SSE (I think SSE3 is 
> needed for 128 bit integer ops?)

AFAIR icc did some vector optimizations in the vinum code at the time
when I worked on getting the kernel "icc-clean", but since we can't use
SIMD in the kernel, I don't know if it is beneficial or not.

Here's the mail about the ported FPU handling, in case someone wants to
play with it:
http://lists.freebsd.org/pipermail/freebsd-arch/2006-March/004932.html

Bye,
Alexander.

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