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## Low Energy Supercomputing159

Faith Singer at TACC writes "The term 'supercomputing' usually evokes images of large, expensive computer systems that calculate unfathomable algorithms and run on enough energy to support a small city. Now, imagine a supercomputer, but run on the electrical equivalent of three standard-size coffee-makers. This year's international supercomputing conference, SC10, will feature the Student Cluster Competition that challenges students to build, maintain, and run the most-cutting edge, commercially available high-performance computing (HPC) architectures on just 26 amps."
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## Low Energy Supercomputing

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• #### Amps = current, not energy.... (Score:5, Informative)

by Anonymous Coward on Wednesday August 25, 2010 @03:02PM (#33373084)

Amps = current, not energy....

• #### Re:Amps = current, not energy.... (Score:5, Informative)

on Wednesday August 25, 2010 @03:06PM (#33373144)
Assuming P=IV, RMS, and in-phase:

P = (26 A)(100E6 V) = 2.6GW, more than twice the amount of power required to travel from 1985 to 1955 or vice versa.

And energy is measured in joules, not amperes...
• #### Re: (Score:2)

Informative? Modders on drugs? I would understand Funny.

• #### I was captain of the team that won last year... (Score:5, Informative)

on Wednesday August 25, 2010 @08:07PM (#33376564)
...Stony Brook University, and the piece that's missing from the summary is 26 amps@120v, (dual circuits, soft capped at draw of 13 each)

Links to more info from the conference: SC10 CC Page [supercomputing.org], rules [supercomputing.org], and app list [supercomputing.org].

The competition is harder than it sounds, you have to build a cluster from the ground up, fit it into the power requirement (which means stripping out redundancies among other things), strip down a distro (we used Debian as a starting point), get the apps optimized, and then run through the data sets. Your team needs to *understand* the apps, the OS, and the hardware in order to win. There are several people from various teams from past years who have moved on to doing their PhDs in comp sci based on work from this competition (At Carnegie Mellon, MIT, and UMich off the top of my head).

It's important too, in a few ways. For one I know I learned more about clusters the first day I started working on the team for this competition back in 2007 than I ever knew before. That knowledge has led to research fellowships, jobs, and knowledge of what I want to (biochemical modeling). It's an experiance that very few undergrads get, and I think that's a shame.

For the industry it's an important highlight of what can be done with a lot of dedication and a focus on wringing the most from your hardware and software. and in doing that we showcase a lot of work that people dont think about. For example our cluster last year ran off a single disk, plus a large ramdisk as scratch exported over QDR infiniband to the compute nodes. No, it's not new, but it was novel to a lot of people who dropped by our booth.

For another, the ASU team was the first time *I* and many others ever saw a windows cluster in the wild.

Competitions like this are important, they showcase technology and introduce it to undergrads early, with positive benefit!
• #### Times voltage times session time (Score:5, Informative)

<tepples@gmai[ ]om ['l.c' in gap]> on Wednesday August 25, 2010 @03:15PM (#33373260) Homepage Journal

Current * voltage = power. In the United States, alternating current from the wall is nominally 115 volts, and 115 V * 26 A = 2990 W. So I think the actual figure was supposed to be 3 kW of power. Run this for one eight-hour day* for 24 kJ of energy per session.

* This can be business hours (if interactive) or the most efficient cooling hours (if batch).

• #### Re: (Score:2)

Any hour is an efficient cooling hour if you're using geothermal for cooling your cluster ;)

• #### Re: (Score:2)

Energy from the wall can be one of several voltages. 120V or 240V for single phase or 440V for three phase power, all of which are available in your typical commercial building.

• #### Re: (Score:3, Interesting)

I seem to recall my PDP11 required 26A on each of 3 phases at 415 volts to power-up, and it had 1Mb or core memory.

And nominally, all the power of a 486! (Actually, it supported 12 users doing data entry.) Not what I called a super computer, even then.

I think my phone outperforms it in proportion to its 16G or memory: 12,000 times more powerful - Now THAT is what I call a super computer!

• #### Re: (Score:2)

Not all buildings get all voltages. Typically a building gets a single "service voltage", which could be (in the USA) 120/240 volts for single phase, 120/208 volts for three phase, or 120/240 volt three phase using a depricated delta wired transformer bank, or 277/480 volt three phase. Canada has a lot of 347/600 volt three phase around (and also a few places in the USA). And in a few places you can get 138.5/240 or 240/416 in three phase. In many places, street lights run on 480 volt single phase or th

• #### Re: (Score:3, Insightful)

You have variable voltage outlets?

• #### Re: (Score:2)

If you're very careful, you can with a 240V outlet, at least the way we do things in the US.

• #### Re: (Score:2)

You have variable voltage outlets?

It's an amazing feature my power company provides. That alternating sag/surge/sag/surge really shows management why they can't slash my power conditioner/UPS budget.

• #### Re: (Score:2)

Get a transformer that steps the voltage to 155 volts. Then you'd be logarithmically right in the middle of the 100-240 volt range most PSUs can handle. That would cover a rather wide range of sags and swells (surge is a transient ... swell is the term for a longer term rise in voltage).

• #### Re: (Score:3, Funny)

Mine's always alternating...

• #### Re: (Score:2)

Standardization is for wimps, and goes against the freedom to innovate (by forcing everyone to buy my newest voltage outlet).
Oops forgot the <sarcasm> tag again.
• #### Re: (Score:2)

It makes me wonder if they can get away with running on a higher voltage for more power..

• #### Re: (Score:2)

They do, during a summer day our 480V nominal circuit gets as high as 502V but is normally in the 490-495V range as the power company tries to push enough power to keep aircon going.
• #### Re: (Score:2)

This year's international supercomputing conference, SC10, will feature the Student Cluster Competition that challenges students to build, maintain, and run the most-cutting edge, commercially available high-performance computing (HPC) architectures on just 26 amps of energy.

Hey, don't tell them that an ampre isn't a measure of energy, because then I wouldn't be able to enter my 46.54 million volt computer (x 26 amps = 1.21 Gigawatts total power dissipation).

• #### Re: (Score:2)

Loophole.

Give me those amps at 130 KV, please.

I'll supply the step-down transformer.

• #### Sure Thing! (Score:5, Insightful)

on Wednesday August 25, 2010 @03:03PM (#33373096)
Can I use as many volts as I'd like?
• #### Re: (Score:2)

Can I use as many volts as I'd like?

Inquiring minds want to know! Lets see, the most we could probably get into the building is 32KV, at 26 amps on a 3 phase line we can use 2.4 MW before crossing their limit. That should be enough for a little bit of supercomputing.

• #### Re: (Score:2)

Am I allowed to use a transformer to boost the voltage before it gets counted as 26 amps?

• #### Mmm... caffeine. (Score:5, Funny)

on Wednesday August 25, 2010 @03:03PM (#33373110) Homepage Journal
I don't know about computers, but you can get a lot of productivity out of humans with the power produced from three coffeemakers.
• #### Re: (Score:2)

Coincidentally, the number of coffeemakers on this floor is...three.

• #### Re: (Score:2)

Meh. At a job a couple of years ago we had free Espresso. Now that'll get you cranking.

• #### Amps? [pedant] (Score:3, Insightful)

on Wednesday August 25, 2010 @03:04PM (#33373114)
Try Joules (in context as a total), or watts (as a measure per unit time).
• #### Re: (Score:2)

You can also save on energy by just turning the computers off when you don't need them. That's why we got remote control PDUs on ours.

• #### Re: (Score:2)

With lights out management VMWare will even do it for you automagically, turn down hosts when demand is low and (now with 4.1) spin them back up in the morning/before batch run time in anticipation of higher load (it will do it on it's own but it's a bit slow).
• #### I hope they're smarter than the article writer (Score:4, Insightful)

on Wednesday August 25, 2010 @03:04PM (#33373116)

"The competition challenges students to build, maintain, and run a cutting edge, commercially available HPC architecture on just 26 amps of energy."

Only problem is that the Ampere is a unit of CURRENT, not energy. It's like saying someone weighs 686 Newtons.

While I understand that if the voltage is kept the same, then the amps are proportional to the energy involved per unit time because W = V x A. However 26 amps at 120 volts for 1 second is not the same energy as 26 amps at 5 million volts for 20 years.

• #### Re: (Score:2, Redundant)

Only problem is that the Ampere is a unit of CURRENT, not energy. It's like saying someone weighs 686 Newtons.

Wait... what? Newtons are a unit of force, weight is force due to gravity. Maybe you meant that it's like saying something weighs X kg or something masses X Newtons?

• #### Re:I hope they're smarter than the article writer (Score:4, Informative)

on Wednesday August 25, 2010 @03:22PM (#33373362)

It's like saying someone weighs 686 Newtons.

Nope, because that would be correct (other than capitalization). Newtons are a unit of force, and weight is the force of gravity on a thing.

It's not even like saying someone weights 100 kg, which is conventional but wrong: weight is not mass, weight is mass*acceleration.

It's more like saying someone weights 150 m/s. That is, it makes no sense whatsoever without supplying some additional information. If I had an instrument that accelerated objects under a constant force for a fixed time I could get a value in m/s that would allow me to compute the weight if I had the force and the time, in the same way it would be possible to get the energy from the amperage if you had the voltage and the time.

• #### Re: (Score:2)

It's more like saying someone's mass is 686 N. You can guess the correct answer if you make a reasonable assumption, but the statement's wrong. (As a minor difference, the acceleration due to gravity is much less variable than the voltage supplied to electrical devices.)

• #### Re: (Score:2)

Not really... 686 N is the scientifically correct way the state something's weight. If you happen to be in an elevator and the elevator accelerates up or down, your weight would change. If you're sitting in a plane and it's taking off or landing, your weight would change too. Your mass in kg, however, wouldn't change. You're still 68kg even though you weigh far less than 680 N on the Moon.

If you're still unsatisfied, just ask Wikipedia: http://en.wikipedia.org/wiki/Weight [wikipedia.org]
• #### Re: (Score:2)

It's exactly like saying someone weighs 100 kg. It's technically nonsensical but commonly done. And it does make sense if you have one extra bit of information (100 kg in a gravitational field of 9.81 m/s or 26 amps of 110 V AC).

• #### Re:I hope they're smarter than the article writer (Score:4, Insightful)

on Wednesday August 25, 2010 @03:43PM (#33373584)

Yup. Just to add some international touch to it: here in central Europe we have 240-250V outlets, which is radically different from the U.S., so putting amperage even with implied voltage is at least confusing and entirely unscientific and shows a lack of understanding about even the most basic principles of unit notations.

• #### Re: (Score:2)

Yup. Just to add some international touch to it: here in central Europe we have 240-250V outlets, which is radically different from the U.S., so putting amperage even with implied voltage is at least confusing and entirely unscientific and shows a lack of understanding about even the most basic principles of unit notations.

Even just in the US, its common to have both 110V and 220V (or is it 120V and 240V? I've seen both numbers used and I remember once reading why, but I don't remember and its mostly irrele

• #### Re: (Score:2)

Nominal is 120V, with +-6V being considered within tolerance. The 240V systems are just provided through a pair of 120V lines at opposite voltage.
• #### Re: (Score:2)

There's also 208V which is across two lines in a 3 phase system.
• #### Re: (Score:2)

It's like saying someone weighs 686 Newtons.

I just felt a disturbance, as if a million swooshes went by at once...

• #### Re: (Score:2)

It's like saying someone weighs 686 Newtons.

Well, a newton is about 0.53 grams (30 Newtons per 16 oz package) so 686 Newtons would be (686 * 0.53)/16 ~ 23 pounds? It's kinda light, but doable for a small child...

What's that? You didn't mean Fig Newtons?

(sigh)

• #### Student Energy Units (Score:3, Funny)

on Wednesday August 25, 2010 @03:32PM (#33373474)

This is a student project so the correct unit of energy is a "Library of Congress Stacked with Red Bull Instead of Books."

Now, you may convert that into Joules, if you care to.

• #### Re: (Score:2)

How much is that in electron volts?

• #### Mountain Dew (Score:2)

The drink of choice at the competition tends to be Mountain Dew :-)
• #### Well.... (Score:4, Insightful)

by jd (1658) <imipak@@@yahoo...com> on Wednesday August 25, 2010 @03:41PM (#33373570) Homepage Journal

This doesn't sound too difficult. The number one power-consumer is cooling. Distributing the same code over a larger surface area would allow you to reduce just how sophisticated and power-hungry your cooling needs to be. Any SIMD code will distribute just fine over such an architecture. If you're really clever, you'd design the cluster as a series of pentagons and hexagons, allowing you to build a geodesic. This would not only maximize the surface area but would also minimize the distance network traffic has to travel, networking being the biggest cause of latency in supercomputing. The really really clever geeks would then set up additional "regional" networks to allow for much higher performance when handling code that needed to talk much more locally, then distribute the code according to those regions. (Essentially, you then have a cluster of clusters.)

• #### Re: (Score:2)

cluster as a series of pentagons

I for one, welcome a Beowolf cluster of Pentagons. Yes, Siree!

• #### Re: (Score:2)

by jd (1658)

You never know, the contention for resources might keep them all out of trouble.

• #### The limit is 26 amps @ 120VAC (Score:5, Informative)

on Wednesday August 25, 2010 @03:42PM (#33373580)
From the project website (http://sc10.supercomputing.org/?pg=studentcluster_rules.html)

The computational hardware (processors, switch, storage, etc.) must fit into a single rack. All components associated with the system, and access to it, must be powered through the two 120-volt, 20-amp circuits, (each with a soft limit of 13 amps) for a total of 26 amps, provided by the conference. Power to each system will be provided via metered power distribution units The equipment rack must be able to physically hold these metering power strips.

This makes it even harder since theyir hardware has to be power balanced between the two power strips. They'll have to come up with some dynamic load balancing between cluster nodes based on power consumption. I guess dual power supplies might help (do dual power supplies draw perfectly balanced power between both power inputs?), but at a loss of power efficiency.

• #### Re: (Score:2)

It would have made more sense to power it at 240 volts. It would have been in balance at any number of loads, and actually reduced the current somewhat as most PSUs run more efficiently at 240 volts than at 120 volts.

• #### Re: (Score:2)

I'm not sure that 13 amps at 240VAC makes any more sense than 26 amps @ 120VAC - if they wanted to make it a single circuit, they could just provide a 30 amp 120VAC circuit.
• #### Repeat post (Score:2)

*Post complaining about amps not being a unit of energy*

*Feeling smug*

*Actually reading thread, then feeling not so smart because 10 people have already mentioned it*

• #### OK, now that the Amps/Watts thing has been sorted, (Score:2)

Let me say that I really, really like this sort of a challenge. 26 Amps at 120V would definitely trip my home's circuit breaker, but it's a certainly an amount of power that's available to mere mortals. I have a feeling that we'll be surprised by all the creative ways the contestants will find to save watts. Since there is no size/clumsiness limit, I have a feeling that the cooling will be done by water pumped from a giant, passively cooling reservoir. (Well, there was a vague mention of "racks" - so maybe
• #### actually, it wouldn't trip your breaker(s) (Score:2)

You'll notice they specified two 120v outlets of 13A each. You could easily run that on two standard home outlets, as long as they were on different circuits.

• #### Re: (Score:2)

Or just put them on ONE circuit with 240 volts.

• #### Let's put CPU's in electric heaters. (Score:3, Insightful)

on Wednesday August 25, 2010 @04:07PM (#33373902)

I've always found electric heaters (including geysers, etc. but mostly environmental heating) a huge waste of low entropy. You can achieve the same goal by powering enough chips -- would work especially well for floor heating. Now, if you're not recycling old computers, it might cost some, but if our only constraint is energy, we can thus create a supercomputer that spends 0 energy "for itself", just by installing this system to a few buildings.

You could even communicate through the power line, thus eliminating the need for a separate network installation. "Buy our @home geyser, that pays for itself!", that sort of thing...

• #### PPFFFT Coffee powered (Score:2)

Aside from his obvious misuse of amperage as an energy unit. Does any of this really make sense, why save power...crank that baby up.
• #### Re: (Score:2)

Power consumption is a critical performance metric for large-scale computing systems.

The whole ponit here is to prove you can do more with a limited resource where that resource is something that computing systems managers are desirous of reducing because it gives them the right to claim all sorts of greenish certification bonads from the marketosphere, and improve their bottom line for the investosphere.

• #### Re: (Score:2)

Sorry, that's ponit[TM].

• #### If watts = volts times amps... (Score:2)

then this means on a 120 volt system, we're talking 3,210 watts to run the thing. That's about 3 kilowatts.

• #### Besides the [P] != A problem (Score:2)

Do they write anywhere how much of the superconducting architecture they have? Number of cores? Flops? Mips? Anything?

Heck, i can build any architecture with a few watts if i am allowed to underclock and only use 4 cores to demonstrate it.

But well.... It was in Texas... Down where hillbilly creationists roam in the educational boards. Probably they where thought in school to strip any experiment of units and sensible numbers and replace these but general claims, so that all theories are equally scientific.

• #### More voltage, please (Score:2)

Most switching mode power supplies work more efficiently at the higher AC voltage of 240 volts. So, what draws 26 amps at 120 volts should typically draw less than 13 amps at 240 volts. You can thus run more than twice as much computer capacity on the same wiring gauge, which means additional savings in energy loss through the wiring feeding to the computers.

Most homes in the USA have 240 volts. If you are going to put a lot of computers in a room, wire up a 240 volt circuit for it. Just be sure to use doub

• #### Stupid contest (Score:2)

Ok, so i'm sure a lot of students learn a lot, but after reading how this contest is run it seems like total BS.

First, with a power budget that small, building a cluster isn't even worth it. A large SMP machine will dominate on any bandwidth limited benchmark. A machine with GPU's is going to dominate any compute bound application. An 8 socket machine (aka DL980G7) packed out with low power 6-8 core processors is going to provide 96-128 threads. Load it up with SSD's, and Tesla's and your probably going to

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