Hi John,

Yes. There are still AMD CPUs sold without SSSE3. Most notably Athlon.
Instead, Intel is providing SSSE3 from the Core 2 Duo.

A detailed list is available at: http://en.wikipedia.org/wiki/SSSE3

Ciao,
Andrea

On Wed, Nov 20, 2013 at 7:09 PM, John Williams <jwilliams4...@gmail.com> wrote:
> On Wed, Nov 20, 2013 at 2:31 AM, David Brown <david.br...@hesbynett.no> wrote:
>> That's certainly a reasonable way to look at it.  We should not limit
>> the possibilities for high-end systems because of the limitations of
>> low-end systems that are unlikely to use 3+ parity anyway.  I've also
>> looked up a list of the processors that support SSE3 and PSHUFB - a lot
>> of modern "low-end" x86 cpus support it.  And of course it is possible
>> to implement general G(2^8) multiplication without PSHUFB, using a
>> lookup table - it is important that this can all work with any CPU, even
>> if it is slow.
>
> Unfortunately, it is SSSE3 that is required for PSHUFB. The SSE3 set
> with only two-esses does not suffice. I made that same mistake when I
> first heard about Andrea's 6-parity work. SSSE3 vs. SSE3, confusing
> notation!
>
> SSSE3 is significantly less widely supported than SSE3. Particularly
> on AMD, only the very latest CPUs seem to support SSSE3. Intel support
> for SSSE3 goes back much further than AMD support.
>
> Maybe it is not such a big problem, since it may be possible to
> support two "roads". Both roads would include the current md RAID-5
> and RAID-6. But one road, which those lacking CPUs supporting SSSE3
> might choose, would continue on to the non-SSSE3 triple-parity 2^-1
> technique, and then dead-end. The other road would continue with the
> Cauchy matrix technique through 3-parity all the way to 6-parity.
>
> It might even be feasible to allow someone stuck at the end of the
> non-SSSE3 road to convert to the Cauchy road. You would have to go
> through all the 2^-1 triple-parity and convert it to Cauchy
> triple-parity. But then you would be safely on the Cauchy road.
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