I haven't seen many benchmarks of the Fujitsu SPARC64 VIIIfx that K computer is supposed to have, yet from the outside it seems to me as a very capable CPU. Complaining one is allowed to do after having a go at it trying to rewrite software for it.
It's simply not realistic in this many core age to suppose you can keep running your software without rewriting it for new architecture, a box which had a cost of 1.4 billion dollar. If you want to take a look in the future with such a 1.4 billion dollar box, then you have to write software that can use it. On Oct 11, 2012, at 1:31 AM, Mark Hahn wrote: >> http://www.sciencemag.org/content/338/6103/26.full?rss=1 > ... >> Interesting claim. What kind of architecture structure would benefit >> Linpack and would hinder real-world applications? > > my guess is they don't like vector. > > the quote appears to be from Jun Makino, the GRAPE guy > (so qualifies as "sour grapes!). there is a hint of critique > in http://jun.artcompsci.org/talks/oookayama20120116.pdf > (which if I read between the lines is saying that for his > kind of astrophysics, he wants accelerator-type architectures, > which differ significantly from vector archs in their relation > of cpu and memory. the "1+3 architectures" table seems to show > a desire for dramatically lower B/F (bytes of memory BW per flop?) > as well as much lower M/F. > > as for linpack being a bad benchmark, that's just bullshit. > it's a benchmark. it's not your application. it does a good job > of telling us about a form of performance that is well-understood. > yes, you can make a very good guess at HPL performance if you know > ncpus, peak FP rate and the interconnect performance - but conversely, > a benchmark which is unpredictable is nothing to brag about! > > as for the criticism of K's process, well, making sausage is ugly. > everything about a big project is sausage-like, and K is a fairly > remarkable success given the range of issues it had to span. > even ignoring the politics and finance, a sparc chip (!) that does > very wide SIMD, with a memory system to support it, a cooling design > to keep it going, and interconnect to scale. > > the only thing that pains me about the whole thing is that I don't > guess > all the lessons learned will be propagated or leveraged. mini-K will > not be coming to a center near you. there won't be an commodity chip > that gets "now with added K sauce"... > _______________________________________________ > Beowulf mailing list, [email protected] sponsored by Penguin > Computing > To change your subscription (digest mode or unsubscribe) visit > http://www.beowulf.org/mailman/listinfo/beowulf _______________________________________________ Beowulf mailing list, [email protected] sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
