Re: [RFC] [PATCH] Add memcpy32 function

[Bryan O'Sullivan]

On Wed, 2005-12-28 at 18:50 +0100, Andreas Kleen wrote:

> Ok thanks. And do you have numbers that show that the assembly
> function with rep ; movsl actually  improves performance over C?

I'll see if I can ferret some numbers out.  If not, I'll generate them,
but it will take me a day or so.  I'm pretty sure it makes a difference
of tens to hundreds of nanoseconds, which in our case is very
significant (we measure some of our user-level performance in increments
of 10ns, very repeatably).

> If the assembly is not really faster I would recommend you just use a
> writel()
> loop in the driver instead of adding this very special purpose function
> everywhere.

Yeah, clearly if there's no difference, it's not worth the trouble.

	<b

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