[Beowulf] 1 multicore machine cluster

Ashley Pittman ashley at pittman.co.uk
Wed Apr 29 12:17:51 PDT 2009

On Fri, 2009-04-24 at 08:19 -0400, Glen Beane wrote:

> I think the term “node” is a loaded term in HPC.  This is what comes
> to mind when I hear node, and I’m sure a lot of other people think the
> same:  A node is a physical building block of a cluster.  It has an
> operating system, it probably has some kind of daemon running to
> launch jobs submitted to a batch system.  It is managed as a single
> unit, but may contain many processors & cores.  I don’t think anyone
> in the HPC field would say that a cluster of 128 systems with 8 cores
> per system is a 1024 node cluster. They would say it is a 128 node
> cluster with 1024 cores. It has 128 operating system instances
> running, 128 pbs_moms, etc.  Calling it a 1024 node cluster is
> misleading.  Much of the management here tend to confuse node with
> core, but we’re a genetics research laboratory and most people don’t
> have a background in this.

There is an awful lot of software around which refers to "nodes" when in
your nomenclature it means core[1], most of it harks back to when nodes
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".

All in it can be confusing, particularly when dealing with
specifications or software which is more than one generation of hardware


[1] Of course I'm actually referring to process here and assuming that
your job has a 1<=>1 mapping of cores to processes.

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