[Beowulf] 8p 16 core x86_64 systems

Joshua Mora joshua_mora at usa.net
Tue Aug 12 11:10:30 PDT 2014

Certainly my assumption/interpretation has been "what is the availability of
the cheapest and largest SMP solution with full coherence in hardware that you
can build". 
Notice I mention hardware based coherence since there are software based
solutions available as well.
If you need just plenty of cores at the highest core count density that you
can get with small memory footprint per OS_instance/core(for instance, for
consolidation/virtualization reasons), then you do not need coherence and a
much wider range of solutions are available that can use other

------ Original Message ------
Received: 10:53 AM PDT, 08/12/2014
From: "C. Bergström" <cbergstrom at pathscale.com>
To: Joshua Mora <joshua_mora at usa.net>Cc: doug.lattman at L-3com.com,
beowulf at beowulf.org
Subject: Re: [Beowulf] 8p 16 core x86_64 systems

> On 08/12/14 11:57 PM, Joshua Mora wrote:
> > Hello Doug.
> > AMD CPUs are connected together with a coherent fabric named
> > It allows to build shared memory system with coherency upto 8 numanodes.
> > Currently, AMD CPUs have 1 numanode or 2 numanodes. The first is in 1
> > package/socket named C32 and the second in a 1 package/socket named G34.
> > The package G34 has 2 numanodes connected with Hypertransport.
> > That is the way you can get in a single package upto 16 cores.
> > Hypertransport technology allows only upto 8 numanodes.
> > Therefore you can have mother boards that connect upto 8 C32 sockets or 4
> > sockets.
> > Hypertransport consortium has designed extensions to overcome this limit,
> > named high (numa) node count.
> > Adding below a link to the specification.
> > http://www.hypertransport.org/default.cfm?page=HighNodeCountSpecification
> >
> > Without the intend to flood this list with marketing BS:
> Not taking away from any of the cool things which you can do with this.. 
> I suspect the OP was trying to increase his density. What you mentioned 
> would require 2 motherboards and also an interconnect between them.
> I believe Cray may have a high density blade setup, but I'm not sure if 
> there's anything like this for mere mortals.

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