[Beowulf] MIPS/Watt data

C J Kenneth Tan -- OptimaNumerics cjtan at OptimaNumerics.com
Fri Jun 4 01:29:31 PDT 2004

To follow on Jim's mail, there was a talk at ICCSA 2004 last month,
given by Steve Smith (Dell) that covered this topic in some detail.
He also covered the issue of efficiency of code and the associated
cost.  The slides are available for download at the conference web
site: http://iccsa2004.unipg.it/plenary/SteveSmith.zip

Kenneth Tan

P/S: I don't mean this to be an advert for OptimaNumerics, but Steve
did mention OptimaNumerics directly in the presentation.  
C. J. Kenneth Tan, Ph.D.
OptimaNumerics Ltd.
E-mail: cjtan at OptimaNumerics.com      Telephone: +44 798 941 7838
Web: http://www.OptimaNumerics.com    Facsimile: +44 289 066 3015

On Thu, 3 Jun 2004, Jim Lux wrote:

> Date: Thu, 03 Jun 2004 10:06:31 -0700
> From: Jim Lux <James.P.Lux at jpl.nasa.gov>
> To: Brian D. Ropers-Huilman <bropers at lsu.edu>, Bari Ari <bari at onelabs.com>
> Cc: beowulf at beowulf.org
> Subject: Re: [Beowulf] MIPS/Watt data
> Not exactly nobody:  I'm VERY interested in minimizing joules per computation,
> because every joule and watt is precious in space....
> Lest you think that my application is peculiar, it really isn't, it's just an
> extreme case of the increasing emphasis on total cost of ownership.  Power
> consumption is going to be more and more important, especially for clusters
> with more than 4-5 CPUs: Ballpark it.. If your node costs $1000/CPU and it
> burns 100W/CPU.  You'll actually need more like 150W/CPU (by the time you pump
> that heat to the big outdoors).  Run that CPU 24/7 for a year, and you've
> burned 1.3 MWh, about $250 dollars worth, a pretty big fraction of the cost of
> the node (a REAL big fraction if you amortize over 3 years). Cut the power in
> half to do your computation, and you've just effectively bought yourself a
> bunch more nodes.
> There are other capital cost aspects to moving the heat around. Taking a quick
> gander at the Grainger catalog... A ductless split system with 23000 BTU/hr
> capacity runs about $2300 and consumes about 2200W (SEER very close to 10).
> 23kBTU/hr is 6.8 kW.  Figuring a 50% overall system efficiency, we get pretty
> close to 3 Watts/dollar. (We'll also assume that includes installation costs,
> etc.)  So, to move that 150W out of the room costs about $50 in capital costs,
> as well. Could be twice or three times that, or half.
> Before people start beating me up about my pessimistic estimates for power and
> HVAC costs, the real point is that reducing the energy consumed to do a unit
> of computation is a "good thing".  There is a distinctly non-zero cost to
> moving the heat away from the CPU to the great outdoors that pervades every
> part of a cluster.  You need bigger heat sinks or heat pipes and bigger fans,
> which makes the chassis bigger and heavier, which means that the rack has to
> be stronger, which means that the floor has to be stronger, and the room
> probably has to be bigger.
> For trivial sized clusters, where you can "fit everything under a desk", this
> is less of an issue, but you start to get any size at all, the infrastructure
> costs start to come out of the noise level.
> I think that in the cluster market, this is where vendors are going to have to
> start competing.  Clearly, they can't try to make deals on the cluster
> software, because (as evidenced by all the discussion on the list of late) the
> software is basically low cost.  A vendor can sell on "quality of hardware",
> but underneath it all, there's only a few mobo manufacturers, so it comes down
> to who gets the best quantity discounts, and who has the best sheet metal
> fabricators, which is a pretty competitive business. The basic cost to design,
> market, and fabricate nodes and racks for a cluster is pretty much the same
> for all vendors.
> So, how, as a vendor, do you differentiate yourself from all the rest?
> (especially if someone wants to make a decision based on quantitative
> metrics.)
> - service: repair frequency and speed, documented low MTBF and MTTR, etc.  -
> these are tough to quantify in any meaningful way, because clusters are still
> essentially "one-off" unique items, so statistics are not particularly
> meaningful.  This comes down to the fuzzy things like "vendor reputation".
> - unique value added: Training, preconfigured systems, etc.  - again, very
> difficult to quantify, because some bright soul at your prospective customer
> will come up with the "why should we pay X all that money, when I can download
> the software, burn the CDS and get it up and running in my spare time"..
> Granted it's bogus, but it happens.  A vendor can't prove that the "do it
> yourself" approach is actually more expensive, and unless the customer has
> built some clusters themselves, they won't know any better.
> - lower cost of ownership - something that is readily quantifiable!  I know
> what electricity costs, what floor space costs, what sysadmin time costs, etc.
> James Lux, P.E.
> Spacecraft Telecommunications Section
> Jet Propulsion Laboratory, Mail Stop 161-213
> 4800 Oak Grove Drive
> Pasadena CA 91109
> tel: (818)354-2075
> fax: (818)393-6875
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