> > I've remembered to check the cluster monkey feed, and > seen > http://www.clustermonkey.net/Opinions/the-core-diameter.html > > The assumption made here is that every node needs to be able > to talk to every other node within the assembly.
Good point, you are correct. I was using the assumption of full bi-sectional bandwidth/latency. On thinking about it, this feature has always a design goal for most HPC systems. Obviously, as we reach more limits, these assumptions will need to be reconsidered. I'll put on note on the article. -- Doug > > I think there is a large class of problems where direct > long-distance communication is not necessary. E.g. if > you're simulating a 3d system with local interactions, > where long-range interactions emerge by propagating > across computational volume in a wave-like fashion > your relativistic limits are only limited to the > geometry of the node and its direct neighbors. > Further nodes will be reached at next refresh, > assuming a relativistic cut-through fabric present > in each node, or computation where information is > passed implicitly by change of state within > adjacent node. > > Such problem classes on such node geometries have > no intrinsic size limit to the number of nodes, > since communication is always limited to overlapping > light cones of subsystems. > > Obviously smaller nodes means higher refresh rate, > so the system asymptotically converges towards a > cellular automaton model, with ~nm sized cells. > It is provably impossible to do classical computing > faster than this. The time domain is rather ~ps > than ~us, and maximally possible refresh rate is > some ~100 PHz for ~nm sized cells. > > Obviously, ability to cool such volumes will limit > such high refresh rates, even if the computation is > reversible (which probably means it has to be > adiabatic, and hence also intrinsically slower). > It also seems that spintronics is not extremely > fast, and spintronics/photonics/plasmonics is > likely to be the modes of computation and > communication used in such future systems. > _______________________________________________ > 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 > > -- > Mailscanner: Clean > -- Doug -- Mailscanner: Clean _______________________________________________ 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
