[Beowulf] The Walmart Compute Node?

Kilian CAVALOTTI kilian at stanford.edu
Fri Nov 9 10:11:46 PST 2007


Hi Vincent,

On Friday 09 November 2007 09:21:41 am Vincent Diepeveen wrote:
> Ok easy theoretic calculation, and it's still very rude of course:
>
> 1 core 2.4Ghz * 3 instructions a cycle * (sse)2 = 7.2 * 2 = 14.4
> Gflop 

Could you please elaborate a little bit about the "3 instructions a 
cycle * (sse)2" part? I thought Intel's quad-core line was able to do 4 
ops/cycle, but you're talking about 6, which makes a huge difference in 
the final numbers.

For instance, theoretical performance using one core of a E5345 
(Clovertown 2.33GHz) would be 9.32 GFlops considering 4 ops/cycle, and 
13.98 GFlops if we consider 6 ops/cyle. Given that the actual measured 
HPL performance on one core is about 7.86 GFlops, it would give an 
efficiency of a mere 56%, which would badly sucks (a 84% efficency is 
more in the line of reasonnable values to me, for one single core).

But I may have missed something.

Cheers,
-- 
Kilian



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