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The Supercomputer Race

samzenpus posted about 6 years ago | from the greased-lightning dept.

Supercomputing 158

CWmike writes "Every June and November a new list of the world's fastest supercomputers is revealed. The latest Top 500 list marked the scaling of computing's Mount Everest — the petaflops barrier. IBM's 'Roadrunner' topped the list, burning up the bytes at 1.026 petaflops. A computer to die for if you are a supercomputer user for whom no machine ever seems fast enough? Maybe not, says Richard Loft, director of supercomputing research at the National Center for Atmospheric Research in Boulder, Colo. The Top 500 list is only useful in telling you the absolute upper bound of the capabilities of the computers ... It's not useful in terms of telling you their utility in real scientific calculations. The problem with the rankings: a decades-old benchmark called Linpack, which is Fortran code that measures the speed of processors on floating-point math operations. One possible fix: Invoking specialization. Loft says of petaflops, peak performance, benchmark results, positions on a list — 'it's a little shell game that everybody plays. ... All we care about is the number of years of climate we can simulate in one day of wall-clock computer time. That tells you what kinds of experiments you can do.' State-of-the-art systems today can simulate about five years per day of computer time, he says, but some climatologists yearn to simulate 100 years in a day."

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The true best measurement (5, Funny)

Anonymous Coward | about 6 years ago | (#25129355)

Is how many libraries of congress it can read in a fortnight.

Re:The true best measurement (1)

A non-mouse Coward (1103675) | about 6 years ago | (#25129443)

Is how many libraries of congress it can read in a fortnight.

PROGRAM HelloWorld
PRINT *, "Hello World"

Re:The true best measurement (2, Interesting)

ari_j (90255) | about 6 years ago | (#25129553)

Define "read."

Exactly. HP PA-RISC vs. 21364 Alpha vs. UltraSPARC (-1, Troll)

Anonymous Coward | about 6 years ago | (#25130209)

Alpha wins. UltraSPARC follows with its memory bandwidth strength. PA-RISC sux a nut. Where i SGI, Intel & AMD?

Transmeta should be every laptop proc.

Re:Exactly. HP PA-RISC vs. 21364 Alpha vs. UltraSP (1)

ari_j (90255) | about 6 years ago | (#25130255)

I was actually referring to the difference between read as in the system call and read as in what you do with a book.

Re:Exactly. HP PA-RISC vs. 21364 Alpha vs. UltraSP (1)

johanatan (1159309) | about 6 years ago | (#25131393)

Way to clarify that for the AC out in left field!! [His plug for Transmeta was complete OT, but you managed to use it as a legitimate 'question'.] Congrats! ;-)

Re:Exactly. HP PA-RISC vs. 21364 Alpha vs. UltraSP (1)

ari_j (90255) | about 6 years ago | (#25131585)

Thanks ... I think. ;-)

Re:The true best measurement (1)

JYD (996651) | about 6 years ago | (#25130837)

Isn't the bottleneck mostly I/O in this case, rather than CPU, since the said operation requires very little floating point operation, which is what the TOP500 is essentially all about.

Thats not a "barrier" (2, Insightful)

quenda (644621) | about 6 years ago | (#25129703)

computings Mount Everest - the petaflops barrier

Two bad cliched metaphors in one! Its not a peak, and its not a barrier, just another arbitrary milestone. Who writes this crap?
Oh ... a "professional" writer from an industry magazine. That figures.
This guy should enter the The Bulwer-Lytton Fiction Contest []

Re:Thats not a "barrier" (1)

im_thatoneguy (819432) | about 6 years ago | (#25129857)

True. And if anything it should be the K2 of computing.

The real problem is once you've overcome the highest peak does that mean all computing is down hill! Hurray for bad analogies!

Re:Thats not a "barrier" (3, Funny)

JustOK (667959) | about 6 years ago | (#25130049)

you're making a mountain of a metaphor

Re:Thats not a "barrier" (1)

morgan_greywolf (835522) | about 6 years ago | (#25130115)

No kidding. A petaflop ought to be enough for anybody!


Re:The true best measurement (1)

blair1q (305137) | about 6 years ago | (#25129833)

a furlong (plus one ear)

Weather Day After Tomorrow (1)

Alan_442 (576793) | about 6 years ago | (#25129365)

I year for the day when they can predict the weather 48 hrs from now and be 99% accurate. Also, the same with hurricanes.

Re:Weather Day After Tomorrow (1)

Alan_442 (576793) | about 6 years ago | (#25129371)

yearn ...that is.

Re:Weather Day After Tomorrow (4, Funny)

smitty_one_each (243267) | about 6 years ago | (#25129477)

The mondo-flop race,
As the hair on your face,
You yearn to displace,
So do it with grace.
Burma Shave

Re:Weather Day After Tomorrow (4, Funny)

Fishbulb (32296) | about 6 years ago | (#25129385)

Don't hold your breath; it'll disrupt the predictions.

Re:Weather Day After Tomorrow (1)

geekoid (135745) | about 6 years ago | (#25129453)

48 hours forecasts are very accurate. Hurricanes aren't so bad either,.
I remember when the big leap was talking about a 3 day forecast to viewers, not it's 7-10. Still with decent accuracy.

Now I note you said 'predictions' and that will never happen. I am assuming you meant forecasts.

Re:Weather Day After Tomorrow (5, Interesting)

geezer nerd (1041858) | about 6 years ago | (#25129653)

I can remember when the big desire of weather simulation supercomputers was to take less than 24 hours to do a 24-hour forecast. IIRC back in the second half of the '70s there was a big government-funded effort to build special fluid-dynamics oriented new machines to break that barrier.

44 years ago 1-5 megaflops was hot! What excitement we felt when the CDC6600 was installed at my university!

Back in '85 I was part of a startup building a mini-Cray, reimplementing the Cray instruction set in a smaller, cheaper box. I remember we focused on the Whetstone benchmark a lot, and it turned out that the Whetstone code really was bound up by moving characters around while formatting output strings, etc. We paid very careful attention to efficiently coding the C library string handling routines, and that got us more performance payback than anything we could do to optimize the arithmetic. One needs to understand the benchmark being used.

Re:Weather Day After Tomorrow (1)

Deadstick (535032) | about 6 years ago | (#25130621)

Well, if you don't know if there's gonna be a hurricane, then you don't know what the weather's gonna be, do you?


Simulation (4, Funny)

gringer (252588) | about 6 years ago | (#25129393)

Simulate 100 years of climate in a day? Here's my code:

echo -e "sunny\nrainy\ncloudy" | rl -rc 36525

Re:Simulation (1)

swillden (191260) | about 6 years ago | (#25129579)

What is rl?

Re:Simulation (2, Funny)

Kneo24 (688412) | about 6 years ago | (#25129603)

Relive! The machines have sentience! RUUUUUUN!

Re:Simulation (3, Informative)

monsul (1342167) | about 6 years ago | (#25129609) []
From the webpage: rl is a command-line tool that reads lines from an input file or stdin, randomizes the lines and outputs a specified number of lines. It does this with only a single pass over the input while trying to use as little memory as possible.
Didn't know about it either. Seems marginally useful

Re:Simulation (1)

Surt (22457) | about 6 years ago | (#25129929)

The Random Line picker.

Re:Simulation (1)

gringer (252588) | about 6 years ago | (#25131715)

It's a simple line randomisation program. I use it a lot in the work that I do for short shell scripts, which involves doing lots of permutations of lines of text files (or just sequences of numbers). Once that code gets put deeper into a loop (and hence becomes more of a limiting factor in terms of excecution time), I substitute it for faster stuff written in Java, Perl, R, C++, or whatever else takes my fancy at the time. shuf is a similar program which seems to be in the coreutils of Debian, but doesn't allow resampling from the brief reading I've had regarding its use.

Re:Simulation (2, Interesting)

GroeFaZ (850443) | about 6 years ago | (#25130191)

You jest, but that's exactly the point. "Simulated years per day" is about as meaningless a metric as it gets, because, as you proved, that number depends on the complexity of the underlying climate model, and also on how well the software was written, i.e. if it is optimized for both the hardware and the model to be computed.

Both these factors are hard/impossible to control and to standardize, and the only factor that does not change is the actual hardware and its peak/sustained performance, so it's the only sensible metric.

Financial modeling and spying better funded (3, Insightful)

Ritz_Just_Ritz (883997) | about 6 years ago | (#25129395)

Sadly, while predicting the weather and better understanding it ultimately helps a lot of people, I suspect a LOT more computing power is thrown at more mundane things like predicting where the financial markets are going to be based on a gazillion data inputs. Probably even better funded are the vast datacenters around the world that fondle communications and other data for the spymasters. I doubt those computing resources are represented in the annual supercomputing lists. :)

Re:Financial modeling and spying better funded (3, Funny)

Quarters (18322) | about 6 years ago | (#25129469)

But, in a roundabout way the financial market simulator will ultimately help the weather simulator's performance. Everyone knows that business apps are written in VB. That means the financial simulator folks need MUCH more powerful supercomputers to run their code at anything close to appreciable speed. That same machine will run well coded weather apps blazingly fast!

Re:Financial modeling and spying better funded (1)

Alwin Henseler (640539) | about 6 years ago | (#25129577)

Right, and let's not forget supercomputers used for simulating nuclear weapon designs, or things like that. Only the latest & greatest is good enough when talking about ways to destroy fellow humans.

Re:Financial modeling and spying better funded (-1, Offtopic)

Anonymous Coward | about 6 years ago | (#25129615)

Because they produce tangible returns on investment.

Despite all the gloom-and-doom, there's still no indisputable evidence than humanity is significantly changing the climate of the planet - despite how much you may WANT that evidence to be there, it just ISN'T.

All we have a computer models - and yet just last year a previously unknown yet massive deep ocean current was discovered. And every single one of the climate models that MODEL man-made global warming did not account for that current.

Re:Financial modeling and spying better funded (1)

The Master Control P (655590) | about 6 years ago | (#25130247)

And by the time we come up with your "indisputable evidence" the northwest passage will probably be ice-free all year round, we'll be in the middle of a mad scramble to raise city ocean barriers another 10 feet because another massive chunk of Antarctica collapsed into the sea, and you'll be demanding indisputable evidence that those calthrate blowouts that are happening more and more up north will be a real problem.

Some problems really are bad enough that they require proactive attention. Stop hiding behind "B b but it has to be indisputable" as an excuse to do nothing.

Re:Financial modeling and spying better funded (1)

sumdumass (711423) | about 6 years ago | (#25131009)

Right now, it is mainly manufactured evidence. There is still a chance that no indisputable evidence will ever be found and that we are barking up the wrong tree.

Before people start blasting me for blasphemy, As soon as you stop looking at things objectively, you stop pursuing knowledge and start believing with faith instead of looking for the truth. I don't care how convinced you might be that X=Y, if there is no room for Y to equal Z without Z equaling X, you have lost the scientific principle and are acting on faith alone. Not being able to falsify something and not being allowed to are very similar and have the same effects.

Re:Financial modeling and spying better funded (1, Insightful)

blair1q (305137) | about 6 years ago | (#25129849)

I suspect no computing power is being thrown at predicting where the financial markets are going.

A lot is thrown at pretending to predict it, but it's brilliantly obvious that the output of such things is no better than chicken entrails or the last two presidential elections.

Something like (1)

Luthair (847766) | about 6 years ago | (#25129933)

90% of Roadrunner CPU time is reserved for the military as I recall.

Re:Financial modeling and spying better funded (1)

PingPongBoy (303994) | about 6 years ago | (#25131593)

I suspect a LOT more computing power is thrown at more mundane things like predicting where the financial markets are going to be based on a gazillion data inputs.

I wouldn't say mundane.

For one thing, any intelligent deep thought requires the gazillion inputs because of the sheer number of factors and an error or bad approximation in just a few inputs could throw off the decision or computation. Granted, the financial markets are typically so frenzied that hardly anyone knows whether to buy or sell, but we would do well to build computers that are capable of market analysis.

Data input is one of the biggest hindrances to computing. Take a typical office, and there are people laboriously entering information because that is the only way to get it right. It shouldn't take petaflops to scan a wrinkled page with scribbles or listen to voice in a noisy room.

Imagine (0, Offtopic)

sexconker (1179573) | about 6 years ago | (#25129399)

Imagine a beowulf cluster of these.

Flops not useful? (4, Informative)

zippthorne (748122) | about 6 years ago | (#25129413)

But.. The whole point is to test the model, and the models change, don't they? Surely we're not just simulating more "years" of climate with the current batch, but improving resolution, making fewer simplifying assumptions, and hopefully, finding ways to do the exact same operations with fewer cycles.

How can you possibly evaluate supercomputers in any other way except how many mathematical operations can be performed in some reference time? And.. some serial metric if the math is highly parallel, since just reducing the size of vectors in those cases wouldn't actually result in those flops being useful for other tasks.

Re:Flops not useful? (4, Interesting)

geekoid (135745) | about 6 years ago | (#25129473)

That's just the problem, people want to hear raw numbers, but those are useless.
How well can it do the specific task it needs to do is the actual question. It's a hard one, to be sure.

Re:Flops not useful? (4, Informative)

jd (1658) | about 6 years ago | (#25130127)

To be honest, I thought most people already knew about and used HPC Challenge, which produces 7 different benchmarks covering different types of mathematical problem, memory bandwidth and communications bandwidth. I also imagined people would use MPI-IO [] for measuring MPI performance, that the numbers on the Top500 was simply because it's hard to track a vast number of stats in a meaningful way.

Of course, if it's actually the case that people are dumb, lazy or in marketing, then that would explain why we don't get a full range of stats, even though the tools have existed for many years and are certainly widely known.

Re:Flops not useful? (5, Informative)

corsec67 (627446) | about 6 years ago | (#25129573)

Flops wouldn't test how well the interconnects work.

Since you say "increase the resolution of the model", you are expanding the size of the model, and how much data must be used by all of the nodes of the computer.

Since how important the interconnect properties are is dependent on the model, with almost no communication needed, like for F@H, to a problem that needs all of the nodes to have access to a single shared set of data, it would be very hard to quantify performance in one number.

Unfortunately, there are more than a few fields where marketers want a single number to advertise in a "mine is bigger than yours" competition, and come up with a metric that is almost worthless.

Re:Flops not useful? (1)

jd (1658) | about 6 years ago | (#25130167)

Oh, and you can perform further diagnostics by using DAKOTA and KOJAK to profile a standard MPI application across the supercomputer. Since these profilers give you internal details, you should be able to see where specifically slow-downs occur - be it a processing quirk, a system library flaw or a networking glitch. Hell, I wish someone paid me to benchmark supercomputers. I can pretty much guarantee RoleMaster fans will love the numbers, even if nobody else can cope with the stats.

Re:Flops not useful? (2, Informative)

ceoyoyo (59147) | about 6 years ago | (#25130749)

Actually, Linpack is not embarrassingly parallel so it DOES test how well the interconnects work, to some extent.

The top 500 list is interesting, but if you're building a supercomputer to make a certain rank you have too much money and you should really give me some.

You build a supercomputer to perform some task or class of tasks. If it gets you on the list, cool.

Re:Flops not useful? (1)

Fishbulb (32296) | about 6 years ago | (#25129749)

Because the climate simulation model they use does a LOT of inter-process communication. Each piece of the calculation depends on what's going on around it.
Ever see footage of manual calculation rooms NASA used to have*? Imagine if every one of the calculations those people were doing depended on the previous calculation they did, AND all of the previous calculations of their eight nearest neighbors.

Now you know why that atmospheric model has a benchmark rated in "century/months" - the number of centuries of "model"-time that can be calculated per month of "wall clock"-time.
That they're working toward a century per day is pretty amazing, especially when they're also tightening the resolution down from 20 sq. km. to under 5 sq. km. by 6+ levels of atmosphere.

* - []

Note: I used to work in the same division of NCAR as Rich Loft. Brilliant guy.

Re:Flops not useful? (4, Informative)

Salamander (33735) | about 6 years ago | (#25129839)

How can you possibly evaluate supercomputers in any other way except how many mathematical operations can be performed in some reference time?

Simple: you evaluate how much actual work it can perform across the entire system per unit time, where "actual work" means a mix of operations similar to some real application of interest. The whole problem here is that practically no real application is as purely focused on arithmetic operations as Linpack. Even the people who developed Linpack know this, which is why they developed the HPCC suite as its successor. It's composed of seven benchmarks, including some (e.g. stream triad) that mostly stress memory and some (e.g. matrix transpose) that mostly stress interconnects. If you want to get an idea how your application will perform on various machines, you determine what mix of those seven numbers best approximates your application, assign appropriate weights, and then apply those weights to the vendor numbers. Then you negotiate with the two or three most promising vendors to run your application for real. SPEC should have put an end to simplistic "single figure of merit" comparisons, or if not them then TPC, SPC, etc. Sadly, though, there's still always someone who comes along and tries to revive the corpse.

Re:Flops not useful? (1)

mr_mischief (456295) | about 6 years ago | (#25130755)

The hard part of that is that my hypothetical high-end supercomputer application and your hypothetical high-end supercomputer application don't do the same thing, and so we must weight those values differently.

To get a single unbiased score, there must be one simple test or a group of unweighted ones. If you're giving an equal weight to different benchmarks, then the overall score might still mean something. The single value from equal weighing still won't be very predictive for applications that stress one part of the system more than others.

It'd be nice if there was a top 500 in each of the HPCC categories and a top 500 overall, but I'm not sure who's going to collect, organize, and present all that info.

Re:Flops not useful? (2, Interesting)

rockmuelle (575982) | about 6 years ago | (#25130381)

"How can you possibly evaluate supercomputers in any other way except how many mathematical operations can be performed in some reference time? "

It's much more subtle than that. Most programs, including weather simulations, use a large amount of data stored on disk and in RAM. The problem with LINPACK as a benchmark is that, for all practical purposes, it ignores this cost by using a few very specific linear algebra operations that have very low communication/computation ratios. The LINPACK number is only relevant if your program is primarily based on operations that have this characteristic.

Unfortunately, most scientific codes (weather simulations included, of course), have evolved past simple implementations based on dense matrix-matrix multiplication (the particular kernel that gives the peak performance number) and include a number of steps that perform closer to the speed of the memory bus than the speed of the processor (sparse matrix operations, which make simulations tractable with millions of variables work this way). There's also the simple fact that very few programmers are even aware of the techniques required to achieve even 50% of peak performance on a kernel as simple as matrix-matrix multiplication. And, the cost of getting past 50% in programmer time is rather high. So, even if scientific codes could be optimally implemented, there's almost no chance they are.

Most people in HPC (myself included) have reached the point where the Top 500 list is a fun curiosity, but has little relevance to actual practice of supercomputing. Optimizing memory bandwidth and interconnects is much more important than raw FLOPS.

Still, I applaud the Roadrunner project. They took some serious risks to pull it off and created a very impressive computer. It's too bad that it will most likely be a one-off implementation (yeah, you can buy QS-22s from IBM, but I doubt they'll be around for too long).


Anonymous Coward (1, Insightful)

Anonymous Coward | about 6 years ago | (#25129431)

The people who want to simulate 100 years of climate a day will, when they get it, want to simulate 2000 years a day.

Re:Anonymous Coward (1)

superdave80 (1226592) | about 6 years ago | (#25129637)

Yeah, that will be real useful.

"There is a 90% chance of rain in Omaha on Wednesday, October 6th, 4008"

Re:Anonymous Coward (1, Insightful)

Surt (22457) | about 6 years ago | (#25129957)

It's marginally more useful if it predicts 0% chance of rain because the average surface temperature of the planet has exceeded 100C on Wednesday, October 6th, 4008

Re:Anonymous Coward (1)

The Master Control P (655590) | about 6 years ago | (#25130317)

Oh, we only wish. Weather is a chaotic system, which means that "nearby" numerical solutions diverge from each other in the system's phase-space at an exponential rate.

Thus, running a simulation longer requires an exponentially shorter timestep to keep the errors supressed. Worse, it also demands exponentially more accurate initial conditions since any initial errors are amplified. I doubt we'll ever see serious "the weather will be..." forecasts for more than a few weeks, mainly due to the IC problem.

Re:Anonymous Coward (0)

Anonymous Coward | about 6 years ago | (#25129683)

They'll just have to move to venus, where they have 5832-hour days. Of course keeping the supercomputer cool is going to be tricky.

Re:Anonymous Coward (0)

Anonymous Coward | about 6 years ago | (#25130259)

No, intel will be releasing a server-farm model that only needs a tent...

Benchmark your application (4, Informative)

straponego (521991) | about 6 years ago | (#25129459)

A quality HPC vendor will give you the opportunity to benchmark your application before you buy a system or cluster. Most will have standard codes installed, but you should also be able to arrange for a login to build and run your own code on their test clusters. This is the only way to guarantee you're getting the best bang per buck, because the bottleneck in your particular applications may be memory, IO, interconnect, CPU, chipset, libraries, OS... An HPC cluster can be a big purchase, and it performance and reliability can make or break careers. Don't trust generalized benchmarks unless you know that they accurately reflect your workload on the hardware you'll be purchasing.

I agree (3, Informative)

friedmud (512466) | about 6 years ago | (#25129479)

I write massively parallel scientific code that runs on these supercomputers for a living... and this is what I've been preaching all along.

The thing about RoadRunner and others (such as Red Storm at Sandia) is that they are special pieces of hardware that run highly specialized operating systems. I can say from experience that these are an _enormous_ pain in the ass to code for... and reaching anything near the theoretical computing limit on these machines with real world engineering applications is essentially impossible... not too mention all of the extra time it costs you in just getting your application to compile on the machine and debug it...

My "day-to-day" supercomputer is a 2048 processor machine made up of generic Intel cores all running a slightly modified version of Suse Linux. This is a great machine for development _and_ for execution. My users have no trouble using my software and the machine... because it's just Linux.

When looking at a supercomputer I always think in terms of utility... not in terms of Flops. It's for this reason that I think the guys down at the Texas Advanced Computing Center got it right when they built Ranger ( [] ). It's about a half a petaflop... but guess what? It runs Linux! And is actually made up of a bunch of Opteron cores... the machine itself is also a huge, awesome looking beast (I've been inside it... the 2 huge Infiniband switches are really something to see). I haven't used it myself (yet), but I have friends working at TACC and everyone really likes the machine a lot. It definitely strikes that chord between ultra-powerful and ultra-useful.


Re:I agree (3, Funny)

Abreu (173023) | about 6 years ago | (#25129663)

My "day-to-day" supercomputer is a 2048 processor machine made up of generic Intel cores all running a slightly modified version of Suse Linux.

We all envy you.

Re:I agree (3, Funny)

jd (1658) | about 6 years ago | (#25130047)

If they'd finished the Berlin GUI, you could have played one hell of a game of Quake.

Re:I agree (0)

Anonymous Coward | about 6 years ago | (#25130757)

Berlin. Ha! That goes back to the furthest reaches of my memory.

But then I'm really drunk right now

Re:I agree (1)

speedingant (1121329) | about 6 years ago | (#25130813)

Its only 3 in the afternoon!!

Re:I agree (1)

Profane MuthaFucka (574406) | about 6 years ago | (#25130405)

I envy his boss. He doesn't have to write any code, but he can go to supercomputer conferences and talk about all the neat things he's doing on his supercomputer.

Well, let's see (5, Interesting)

Louis Savain (65843) | about 6 years ago | (#25129715)

It's about a half a petaflop... but guess what? It runs Linux!

This sounds kind of nice but why should this make it any easier to write parallel programs for it? You still have to manage hundreds if not thousands of threads, right? This will not magically turn it into a computer for the masses, I guarantee you that. I have said it elswhere [] but parallel computing will not come of age until they do away with multithreading and the traditional CPU core [] . There is a way to build and program parallel computers that does not involve the use of threads or CPUs. This is the only way to solve the parallel programming crisis. Until then, supercomputing will continue to be a curiosity that us mainstream programmers and users can only dream about.

Re:Well, let's see (2, Insightful)

friedmud (512466) | about 6 years ago | (#25131697)

"Until then, supercomputing will continue to be a curiosity that us mainstream programmers and users can only dream about."

I'm not so sure that's a bad thing... most applications don't need the power of a super computer...

At the same time, I agree that I wish that desktop development tools made it easier to do threading for multi-core machines. Every new computer comes with more than one core... but the development tools (languages, compilers, IDE's, debuggers) simply aren't helping the everyday joe programmer out there make use of them...


RoadRunner (2, Insightful)

Anonymous Coward | about 6 years ago | (#25129735)

Is running relatively stock Fedora (the ppc distribution). True, it's ram hosted, but the OS is hardly specialized in terms of libraries and such. You could say the Cell SDK is a tad specialized, but the underlying platform is not so custom as implied.

In fact, every single Top500 system I've ever touched has been far more typical linux than most people ever expect.

In any event, the most compelling aspect of RoadRunner in my view is the flops/watt. Application developers who can leverage highly parallel clusters are those who have the best shot of taking adequate advantage of something like the cell architecture, which is admittedly a pain for those that are accustomed to no more than 1 or two concurrent heavy-loaded processes or threads.

BTW I still hate the Infiniband cabling with a passion. Even as they've made it less bad over time, it's still a huge connector. Nothing like Quadrics, mind you, but still reminiscent in bulk to 10base5.

Re:RoadRunner (2, Informative)

friedmud (512466) | about 6 years ago | (#25131575)

The specialization of the hardware / software combo is what I was referring to.

Have you ever coded for one of these special architectures? It really is a bitch. Yes, Redstorm is even worse (special OS that doesn't even allow dynamic linking!)... but the non-generality of the cell-processors is going to kill the real world impact of Roadrunner.

ASCII Purple was one of the previous machines at LANL that was a "one-off" build from IBM. It was a complete disaster. Porting code to the machine took much longer than usual and any person who could show that they were successfully running _anything_ on the machine got a pat on the back. I had the luxury of porting some software to it... good god, just thinking about it makes me want to blow my brains out...

I can't believe they've gone down that same path again.


Re:RoadRunner (2, Informative)

friedmud (512466) | about 6 years ago | (#25131837)

Sorry... got my supercomputers mixed up... ASCII Purple was at LANL...

I was thinking of ASCI Q, but that was made by HP...

Oh... just nevermind... I screwed it up well enough, just forget it ;-)

Need to get some sleep.


Re:I agree (3, Insightful)

CronoCloud (590650) | about 6 years ago | (#25129765)

The thing about RoadRunner and others (such as Red Storm at Sandia) is that they are special pieces of hardware that run highly specialized operating systems.

from []

The Roadrunner uses Red Hat Enterprise Linux along with Fedora as its operating systems and it's managed with xCAT distributed computing software.

Please stop linking to Wikipedia (1, Interesting)

Anonymous Coward | about 6 years ago | (#25130451)

We need a new moderation: -1 Wikipedia Googlebomb. Yes we know you can look things up in Wikipedia. But every time you make a link to Wikipedia from Slashdot, Wikipedia goes up in the Google Page Rankings. And then people act all surprised when Wikipedia is in the top ten for every Google search. Every time you link to Wikipedia, it gets a little bit more powerful.

So instead, why not link to some other relevant page [] ? In this case, link to the owner of the Roadrunner supercomputer. You can probably even go to Wikipedia to get the link. If Wikipedia has a great page on something, don't link to it, just put the plaintext name in like this: "Search for IBM_Roadrunner on Wikipedia."

Please everybody, stop linking to Wikipedia. You're destroying the internet.

Re:I agree (1, Interesting)

Anonymous Coward | about 6 years ago | (#25130799)

Yes, but Roadrunner uses the new Cell SPUs - very different hardware from a typical x86-based cluster.

Red Storm, if I recall correctly, runs a minimalist Linux kernel - something called Catamount, or Compute Node Linux, or something along those lines. Basically, it lacks some features of a full Linux kernel, including various I/O capabilities, but frankly I haven't heard of people having a hard time using Red Storm.

Re:I agree (1)

friedmud (512466) | about 6 years ago | (#25131627)

I will just say that it was about a year before any meaningful calculations were run using Redstorm...


Cost per computing power (2, Insightful)

pimpimpim (811140) | about 6 years ago | (#25129837)

Not just buying the thing, also the cost of maintaining it (standard hardware is most likely easier to maintain), and the power it and its cooling system uses, check green500 for that one. Actually, as a user, I have often found that most supercomputing clusters are inefficient for at least the first year-and-a-half due to imperfect queuing systems or network/filesystem incompatibilities. "Yeah, your run will likely crash every now and then but we don't know yet why". I do not blame the administrators, I blame the suppliers for not working on solutions to make it easier to successfully operate a cluster, e.g. via standardized methods .

As for top500: really, quit with this political joke benchmark. E.g. In molecular simulations alone you will spend on a computer which has either broad memory access for matrix inversions in quantum calculations. Or on a high clock speed, low bandwidth one for MD, which basically does nothing but floating point operations. The score in the top500 will give you 0 information about what machine to choose.

Re:I agree (1)

blair1q (305137) | about 6 years ago | (#25129881)

Your users don't really need that kind of power, then. They could get by using much less of a computer, because they're spending less time coding and have time for running. In fact, I suspect about 70% of your users could get by on a 4x4 card if they ran it and went on vacation for the summer.

The really big HPCs can tolerate the really big software development efforts because the runtime saved by the specialized OS may more than discount the extra development effort.

Re:I agree (1)

friedmud (512466) | about 6 years ago | (#25131609)

"he really big HPCs can tolerate the really big software development efforts because the runtime saved by the specialized OS may more than discount the extra development effort."

The thing is... that might be true for a very select number of projects... and that number of projects is actually smaller than most people think.

Yes, my code can run up to 3 or 4 thousand processors nicely... to get some really high fidelity engineering simulations... _but_ most people are running in the 64 to 128 processor range day to day and only very rarely need the kind of fidelity that comes from half a petaflop or more.

And therein lies the rub: While "potato-flop" computing sounds great... there really just aren't compelling reasons to move to it. The best justification is in analyzing natural phenomenon such as the weather. For engineering simulation (which is what LANL is all about) there are so many sources of error, that running these high fidelity simulations actually doesn't mean anything. A lot of the time the codes that "really make use of the supercomputer" are complete pieces of crap that take _many_ shortcuts in order to make sure that they execute efficiently on these oddball architectures.

I don't mean to sound all down on it... afterall this really is how I make my living. I just mean that from the outside looking in it's hard to see that Flops != good.


Re:I agree (1)

SL Baur (19540) | about 6 years ago | (#25129935)

My "day-to-day" supercomputer is a 2048 processor machine made up of generic Intel cores all running a slightly modified version of Suse Linux. This is a great machine for development _and_ for execution. My users have no trouble using my software and the machine... because it's just Linux.

I am in awe of you, sir.

May I ask out of curiosity, how long it takes to compile the kernel on such a magnificent beastie?

Re:I agree (0)

Anonymous Coward | about 6 years ago | (#25130653)

Not as fast as you might think, and besides you'd have to submit it as a batch job. Relatively few CPUs are dedicated to interactive use on such systems (if any at all).

(Not the OP, but used to admin a very similar system.)

Re:I agree (0)

Anonymous Coward | about 6 years ago | (#25130889)

It takes about as long to compile a kernel as on any other system. You don't have to submit it as a batch job.

These machines, while having somewhat specialized hardware, are basically just lots and lots of computers with a fast interconnect.

You build a kernel and copy it out. It's not a big deal.

Re:I agree (1)

friedmud (512466) | about 6 years ago | (#25131457)

Not very long with distcc....

Re:I agree (1)

SL Baur (19540) | about 6 years ago | (#25131813)

The only time I was employed doing kernel hacking was at NEC and the "big" machine they gave me for testing had ~1GB with 2 CPUS (in 2002). Sigh. Gone are the days...

Non-story... (2, Insightful)

Kjella (173770) | about 6 years ago | (#25129497)

...ever looked at gaming benchmarks? Server benchmarks? Productivity benchmarks? Rendering benchmarks? In fact, any kind of benchmark? Seen how they all differ depending on the product and test run? Same with supercomputers, you got some synthetic benchmarks, and you got some real world benchmarks. But the weather simulation may not be a relevant benchmark at all if you're doing nuke simulations or gene decoding or finite deformation or some other kind of simulation. Synthetics are the lowest common denominator - you'd rather see benchmarks in your field, and most of all benchmarks with your exact application. That doesn't change that those are individual wants and synthetic benchmarks are the only ones with any value to everyone.

The Turk.. (1)

stevedmc (1065590) | about 6 years ago | (#25129623)

Isn't "The Turk" supposed to be the worlds most powerful computer?

Like any benchmark... (2, Interesting)

Junta (36770) | about 6 years ago | (#25129657)

Just with a lot more dollars behind it...

Every one remotely engaged in Top500 systems knows how very specific the thing being measured is. It's most sensitive to the aggregate clock cycles and processor architecture, and not as sensitive to memory throughput/architecture or networking as many real world things are. []

Is an attempt to be more comprehensive, at least, by specifying a whole suite of independently scored benchmarks to reflect the strengths and weaknesses of things in a more holistic way. Sure, it's still synthetic, but it can give a better 'at-a-glance' indicator of several generally important aspects of a supercomputer configuration.

The thing probably inhibiting acceptance of this is that very fact, that it is holistic and the winner 'depends' on how you sort the data. This is excellent for those wanting to more comprehensively understand their configurations standing in the scheme of things, but hard for vendors and facilities to use for marketing leverage. Being able to say 'we built *the* fastest supercomputer according to the list' is a lot stronger than 'depending on how you count, we could be considered number one. Vendors will aggressively pursue pricing knowing about the attached bragging rights, and facilities that receive research grant money similarly want the ability to make statements without disclaimers.

Rest assured, though, that more thorough evaluations are done and not every decision in the Top500 is just about that benchmark. For example, AMD platforms are doing more strongly than they would if only HPL score is counted. AMD's memory performance is still outrageously better than Intel and is good for many HPC applications, but Intel's current generation trounces AMD in HPL score. Of course, Intel did overwhelmingly become popular upon release of their 64-bit core architecture based systems, but still..

Is it *REALLY* the Top 500? (2, Interesting)

Anonymous Coward | about 6 years ago | (#25129671)

Most of the locations listed are mostly educational institutions, r&d centers, and computer companies. The results were probably submitted unofficially. There are few exceptions, but they are just that--few. It makes you wonder what the Big Data companies (Google, Yahoo!, etc) actually have running. They have no reason to participate, after all...

Consider something like Yahoo!'s research cluster [] . Why isn't it on this list? Why don't they run the tests?

How appropiate, (1)

Abreu (173023) | about 6 years ago | (#25129711)

That an article about featuring IBM supercomputers comes shortly after a few misguided individuals were posting that "IBM is no longer relevant, they are a OEM reseller nowadays" or that they "only make bloated, slow software"

I think it is in phases.. (1, Insightful)

Anonymous Coward | about 6 years ago | (#25130153)

IBM retains their engineering, but sometimes the business decision makers fail to understand the value of that, and try to profit by slapping IBM logo on other company's products.

Let's presume we start with an outsourced generation of products. IBM does it and gets slapped with warranty/service costs/get complaints from the services organizations saying they cannot build quality solutions on random white-box systems, and generally customers see little product differentiation from the companies whose products IBM are reselling at increased price.

Then they have a generation of good, IBM-engineered product that uses their in-house engineering teams to produce product. The products work well, and the customers and IBM services business can consistently build upon them.

Then, they decide it's going so well, if only they could cut costs by outsourcing, and the vicious cycle continues.

Uhh, do you have a model? (1, Offtopic)

Mike Rice (626857) | about 6 years ago | (#25129743)

"State-of-the-art systems today can simulate about five years per day of computer time, he says, but some climatologists yearn to simulate 100 years in a day."

IANAM (I am not a meteorologist) like Mr Loft, so excuse me please if I am wrong, but does not the current state of the art in weather modeling provide something like a 3 day preview of the future, with only 50% accuracy?

I submit that Mr Lofts complaints have much more to do with the current mathematical model limitations, than with the ability of current hardware.

This is not a hardware issue (yet). This is still a mathematical issue, and has not one iota to do with the prowess of any computational hardware.

When Mr Loft presents a 100 year weather model with 50% accuracy, I might begin to worry about whether our CPUs can handle it.

Until then I keep my eyes glued on the Weather Underground.

Re:Uhh, do you have a model? (4, Informative)

TapeCutter (624760) | about 6 years ago | (#25129961)

I just threw away a couple of mod points to bring you this announcement: Climate != weather, climate is the long term statistics of weather. Two different numerical analysis models, both computationally expensive.

Re:Uhh, do you have a model? (1)

sumdumass (711423) | about 6 years ago | (#25131201)

The problem is that separating climate from weather doesn't mean much when doing predictions. You still have to predict the weather to provide data points for the climate. Otherwise, you can't have long term statistic of weather patterns in the future that were predictions of today. And you can't make claims about the weather in the future from the climate predictions.

So all future climate predictions will inherit inaccuracies from weather prediction. They are not separable even when you show how they aren't the same. Well, that is unless climate predictions throw the entire long term statistics of weather out the window but then it wouldn't be climate according to your own definition.

Re:Uhh, do you have a model? (1)

TapeCutter (624760) | about 6 years ago | (#25131441)

"And you can't make claims about the weather in the future from the climate predictions."

Can't I? - On average the weather will be colder in winter 4008 than it will be in summer 4008.

The rest of the logic in your post is upside down, however we have crossed swords before and I have (in the past) provided you with relevant links that you are still choosing to ignore.

Re:Uhh, do you have a model? (3, Informative)

Waffle Iron (339739) | about 6 years ago | (#25130183)

IANAM (I am not a meteorologist)

That's for sure.

Here's an analogy: Say you pour two different colored cans of paint into a bucket and start stirring. Weather is like predicting the exact patterns of swirls that you'll see as the colors mix. Very hard to do looking ahead more than a couple of stirs.

Climate is more like predicting the final color that will result after the mixing is done. Not nearly so intractable. The summary is talking about climate, not weather.

Re:Uhh, do you have a model? (0)

Anonymous Coward | about 6 years ago | (#25130407)

Here's an analogy: Say you pour two different colored cans of paint into a bucket and start stirring.

Red is like the color your ass is going to be when your dad finds out you've wasted two cans of paint. Period!

Re:Uhh, do you have a model? (0)

Anonymous Coward | about 6 years ago | (#25131225)

That's for sure.

Thanks for showing your superiority. That's fine and all but could you please rephrase in the form of a car analogy?

Accuracy? (1)

Hatta (162192) | about 6 years ago | (#25129773)

Number of simulated years per day isn't exactly the metric you want. I can simulate a million years in a minute on my home pc, just not very accurately. As you get more accurate, the sim years/CPU day will decrease.

So knowing the number of simulated years per cpu day doesn't tell you anything unless you know exactly what algorithm you're using.

Re:Accuracy? (0)

Anonymous Coward | about 6 years ago | (#25130535)

So knowing the number of simulated years per cpu day doesn't tell you anything unless you know exactly what algorithm you're using.

Which of course is current climate models. There are a number of "standard" models being used these days and that's what's being talked about here.

#1 is IBM's Roadrunner (0)

Anonymous Coward | about 6 years ago | (#25129951)


But will it run Crysis?

Fortran? (1)

actionbastard (1206160) | about 6 years ago | (#25129971)

Why don't they code LINPACK in COBOL [] ?

This is common knowledge (2, Interesting)

Raul654 (453029) | about 6 years ago | (#25130269)

It's fair to criticize Linpack for being a one-trick pony. It measures system performance for dense linear algebra, and nothing else. Jack Dongarra (the guy who wrote Linpack and maintains the top 500 lists) is quite up-front about Linpack's limitations, and he thinks that using a single number as the end-all-be-all of a computer's performance is a bad idea. It's a simple fact of life that certian kinds of computers do better on certain problems. The good guys out at Berkeley even sat down a couple years ago and enumerated [] all of the problems they found in real-world HPC applications (See the tables on pages 11-12). The real truth here is that people should stop treating Linpack like it's the final measure of system performance. If you are doing pure linear algebra problems, it's a pretty good measurement for your purposes; if you are not, then you use it at your own peril.

Oblig (1)

PietjeJantje (917584) | about 6 years ago | (#25130353)

They should just run Vista on them to use as a benchmark. That will effectively flood bottlenecks on all kinds of levels.

Re:Oblig (1)

setagllib (753300) | about 6 years ago | (#25130873)

What's even funnier is the reality that Windows can't even boot on that many CPUs, let alone scale to utilise them.

You can simulate 100 years/day on your laptop (1)

HoneyBeeSpace (724189) | about 6 years ago | (#25130625)

The thing about climate models is that they get more complex and higher resolution as soon as the computers get faster. We will always take about 3 months to run a simulation. You can run it faster? Make it more detailed. It takes longer? Wait a few months to a year and it'll only take 3 months. Why 3 months? Not sure. Partly because that is about the length of a funding cycle of design experiment, run it, analyze, and write it up.

If you want to run 100 years per day, you can do so with an older model. The EdGCM [] project has wrapped a NASA global climate model (GCM) in a GUI (OS X and Win). You can add CO2 or turn the sun down by a few percent all with a checkbox and a slider. Supercomputers and advanced FORTRAN programmers are no longer necessary to run your own GCM.

Disclaimer: I'm the project developer.

Isn't Modeling Weather Futile? (2, Interesting)

CleverMonkey (62124) | about 6 years ago | (#25131297)

I seem to recall a Nova special I watched many moons ago about "strange attractors" and "fractal behavior" that seemed to indicate that for a large class of complex-valued iterative functions there was a weird phenomenon called the "Butterfly Effect". Apparently... according to this show I saw 20 years ago (and I think that Mandelbrot mentioned it in a lecture I attended a few years later), initial variables which are as intertwined as the rational and irrational numbers can have drastically divergent outcomes in these situations.

It seems that the reason that this was called the Butterfly Effect was actually because the disturbance caused by a butterfly could be enough to change the track of a massive storm some days later. ( Reference [] )

The fact is that the weather forecasters on the local broadcast channel are less accurate than if they always predicted sun in one study:

"The graph above shows that stations get their precipitation predictions correct about 85 percent of the time one day out and decline to about 73 percent seven days out.

"On the surface, that would not seem too bad. But consider that if a meteorologist always predicted that it would never rain, they would be right 86.3 percent of the time. So if a viewer was looking for more certainty than just assuming it will not rain, a successful meteorologist would have to be better than 86.3 percent. Three of the forecasters were about 87 percent at one day out â" a hair over the threshold for success."

(ref: [] )

It's a wonderful idea that we can model the incredibly complex climate of our huge planet, but I'll believe it once I can trust the weekend forecast before Friday.

Any other ideas about useful purposes to put these huge computers to? Perhaps accounting and auditing for the new Emergency Financial Legislation?

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