* Posts by UK Jim

5 posts • joined 8 Mar 2012

Swiss super pushes USA off podium in new Top500 Supers list

UK Jim

Titan History

"and in the process bump the “Titan” machine at the USA's Oak Ridge National Laboratory off the podium for just the third time in the history of the TOP500 list of the world's mightiest supercomputers."

Really!? This is the third time that Titan has dropped out of the top 3?

I think what you were trying to say is "and in the process made this only the third time in the history of the list when the USA has no machine in the top 3".

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Little ARMs pump 2,048-bit muscles in training for Fujitsu's Post-K exascale mega-brain

UK Jim

Auto vectorization...

While you can force vectorization of that code (as you do by using compiler flags), doing so is not, in general, safe. Consider an invocation of vectorize_this in which a and either b or c point into the same array. (E.g. vectorize_this(&b[1], b, c);). There is now a loop carried dependence and the results generated by the vector code will be different from those generated by the scalar code.

If you know that the code is used without such overlaps, then the right answer is to modify the code and use the "restrict" qualifier on the arguments to inform compiler of that fact. Though then, of course, you can't claim not to have to modify the code!

(FWIW I work for Intel, and this is an issue for everyone...)

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Picking apart the circuits in the ARM1 – the ancestor of your smartphone's brain

UK Jim

Since Sophie Wilson has the circuit diagrams, why bother with the reverse engineering!? It's really not *that* long ago, so the people who did this are still around, know what they did, and can explain it if you ask!

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Company you never heard of builds 3.4 petaflops super for DOE

UK Jim

Re: since when

Intel acquired the Infiniband assets of Qlogic about a year ago...

http://newsroom.intel.com/community/intel_newsroom/blog/2012/01/23/intel-takes-key-step-in-accelerating-high-performance-computing-with-infiniband-acquisition

(FWIW I work for Intel, but I do not speak for them :-))

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SUPERCOMPUTER vs your computer in bang-for-buck battle

UK Jim

Re: What, no phone?

There are a variety of Linpack ports for Android, some results are at http://www.greenecomputing.com/apps/linpack/linpack-by-device/ for instance...

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