[Beowulf] Multicore Is Bad News For Supercomputers

Mark Hahn hahn at mcmaster.ca
Fri Dec 5 05:44:43 PST 2008

> (Well, duh).

yeah - the point seems to be that we (still) need to scale memory
along with core count.  not just memory bandwidth but also concurrency
(number of banks), though "ieee spectrum online for tech insiders"
doesn't get into that kind of depth :(

I still usually explain this as "traditional (ie Cray) supercomputing
requires a balanced system."  commodity processors are always less balanced
than ideal, but to varying degrees.  intel dual-socket quad-core was 
probably the worst for a long time, but things are looking up as intel
joins AMD with memory connected to each socket.

stacking memory on the processor is a red herring IMO, though they appear
to assumed that the number of dram banks will scale linearly with cores.
to me that sounds more like dram-based per-core cache.

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