AMD bulldozer and GMP

[Rick C. Hodgin]

Vincent,

I believe AMD is working on a CPU design that will eventually allow them
to switch from an x86-based ISA to one ARM-based.

I could be wrong.  Probably am.  But there are many signs.

Best regards,
Rick C. Hodgin

On Sat, 2012-02-18 at 11:08 +0100, Vincent Diepeveen wrote:
> Rick,
> 
> you can prove that throughput of bulldozer is not more than from the  
> quadcore intels.
> In the end bulldozer decodes 4 instructions a cycle a module and  
> intel decodes 4 instructions a cycle a core,
> and bulldozer is a tad slower then than the intels as its caches are  
> a lot slower.
> 
> For parallel well scaling applications that is why bulldozer always  
> will lose it from quadcore intels.
> 
> Besides - they really overclocked bulldozer a lot to get where they  
> are now.
> 
> GMP is such a highly optimized software product that integer  
> multiplication dominates and i bet in bulldozer
> they added huge latencies there in order to overclock bulldozer a lot  
> to be at least nearby the intel quadcores.
> 
> On Feb 15, 2012, at 12:54 AM, Rick Hodgin wrote:
> 
> >> It is totally incomprehensible what AMD is doing.
> >> The new processor runs hot, slowly, and hardly
> >> outperforms a 5W processor for integer number
> >> crunching.  OK, they do, thanks to a 2x clock and
> >> a more cores. But clock-for-clock they are equal.
> >
> > There was a lot of surprise in the CPU community when AMD released  
> > its early Bulldozers for internal benchmarking.  The additional  
> > cores provided far greater throughput overall, but so much was lost  
> > for lesser-parallelized applications that everyone was left  
> > scratching their heads and wondering what was going on (as you are  
> > doing now).
> >
> > AMD was also surprised by its performance actually, indicating to  
> > many that it was an unexpected condition.  Yet, in the end there  
> > were some fixes made but nothing to bring it up to par with what  
> > everyone (outside of core development??) was expecting.
> >
> > Best regards,
> > Rick C. Hodgin
> >
> > _______________________________________________
> > gmp-discuss mailing list
> > gmp-discuss at gmplib.org
> > https://gmplib.org/mailman/listinfo/gmp-discuss
> >
>