> Just to be awkward, there are of course machines like the SGI Altix. > Is it a cluster, or is it a node? From the programmer's perspective > it's the latter, from the architectural perspective, the former. > > There's no real dividing line; there are machines across the entire > spectrum. But I'm just being difficult, generally I agree with what > the others have said.
I'd say definitely the former - a cluster where the nodes (two sockets) are connected using Numalink. I have been thinking long and hard about those classification issues when I was designing sufficiently generic but consistent machine description for our benchmarking database. The view that I took is that there is a "node" which is a reasonably independent entity and you take those nodes and glue them together using some sort of "interconnect". So far this architectural view has not failed me but it is not impossible that future machines might have more intricate "node" or "interconnect" structure and therefore require more sophisticated approach. Programmer's view can't be used for classification purposes because there can be several views on the same hardware at the same time. The Altix example is admittedly blurred but even a traditional cluster can be programmed a la SMP using Cluster OpenMP or other similar approaches which obviously do not make the underlying hardware any different. As for the terms processing element (PE) and core, PE was clearly preferable for machine description rather than core because PE is more generic whereas the term "core" usually implies a fully functional processor that has been shrank. Terminologically PE may include processor cores, SPEs in Cell BE, GPGPUs attached to the node or accelerating co-processors. _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
