[Beowulf] 1 multicore machine cluster
hahn at mcmaster.ca
Wed Apr 29 12:38:56 PDT 2009
>> I think the term ´node¡ is a loaded term in HPC. This is what comes
I think it's just a bit sloppy or at least contextual - I've never
heard it used for anything other than "box". a node on a conventional
message-passing cluster is clearly one computer, which may contain
multiple cores, but has a single memory domain. on an Origin/Altix,
people seem to prefer "brick", but sometimes use "node", and is obviously
not a single memory domain. MPI programmers usually use "rank" or
"processor", and don't get hung up on nodes.
> There is an awful lot of software around which refers to "nodes" when in
> your nomenclature it means core, most of it harks back to when nodes
hmm, a contrary example is gromacs - it explicitly talks about nodes
but permits threads within a node. ie, an 8-core box could be a single
node with 8 threads or 8 nodes, 1th each.
incidentally, any gromacs experts comment on scalability of using
the thread support? (ie, for four 8c boxes with IB, 32 nodes vs
4 nodes, 8 threads each?)
> had one CPU and a CPU had one core. Even the concept of cores
> themselves are only six or seven years old, before then a CPU was just a
> CPU and you would refer to "a N CPU cluster".
and to be on the safe side (wrt forms of simultaneous multi-threading),
we should probably try to use "thread" instead. meaning a single
hardware execution context.
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