Some thoughts about steerring commitee work

[Ira Rosen]

"Daniel Berlin" <dberlin@dberlin.org> wrote on 16/06/2007:

> On 6/16/07, Dorit Nuzman <DORIT@il.ibm.com> wrote:
>
> > Do you have specific examples where SLP helps performance out of loops?
>
> hash calculations.
>
> For md5, you can get a 2x performance improvement by straight-line
> vectorizing it
> sha1 is about 2-2.5x
>
> (This assumes you do good pack/unpack placement using something like
> lazy code motion)
>
> See, for example, http://arctic.org/~dean/crypto/sha1.html
>
> (The page is out of date, the technique they explain where they are
> doing straight line computation of the hash in parallel, is exactly
> what SLP would provide out of loops)

I looked at the above page (and also at MD5 and SHA1 implementations). I
found only computations inside loops.
Could you please explain what exactly you refer to as SLP out of loops in
this benchmark?

Thanks,
Ira