Supercomputers To Move To Specialization?

lucasw writes "The Japan Earth Simulator outperformed a computer at Los Alamos (previously the world's fastest) by a factor of three while using fewer, more specialized processors and advanced interconnect technology. This spawned multiple government reports that many suspected would ask for more funding in the U.S. for custom supercomputer architectures and less emphasis on clustering commodity hardware. One report released yesterday suggests a balanced approach."

Comments

Cost comparison?

[Tyrdium]

Ignoring size, how does the cost of a cluster of fewer, highly specialized computers (with special interconnects, etc.) compare with that of a cluster of more, less specialized computers?

performance vs cost

[harmless_mammal]

Teraflops per dollar is important, let's not forget that.

Specialization

[bersl2]

If you're going to have a supercomputer do one thing, of course specialize it. An Earth simulation surely has a set number of formulae whose calculations are to be optimized as much as possible, even to the hardware level.

But if you want a versitile, general-purpose supercomputer, why not go with the clustering solution?

This greatly surprises me

[ikewillis]

As an employee of an atmospheric modelling group I am very surprised to hear this. Our atmospheric modelling program, the Regional Atmospheric Modelling System, is not I/O bound in the slightest and is instead very much CPU bound. We currently use 100bT for the interconnect on our cluster, and have tried moving to Gigabit with negligable performance gains.

The main area in which we saw benefit was switching from the Portland Group Fortran Compiler to the Intel Fortran Compiler, which cut the timestep (simulation time/real time) nearly in half.

Every cluster in the department is assembled from commodity x86 components. Groups here have been moving from proprietary Unix architectures to Linux/x86 systems and clusters. Our group started out on RS/6000s, then moved to SPARC, and is now moving to x86. In terms of price/performance there really is no comparison.

As for TCO, the lifetimes of clusters here are relatively short, one or two years at the most. Thus a high initial outlay cannot be set by lower cost of operation.

Re:This greatly surprises me

[FullyIonized]

And I'm surprised to hear that you are surprised since fluid modeling is one of the applications that do very well with the vector processors that the Earth Simulator uses. I attended a lecture by Dr. Sato, head of the Earth Simulator, who stated that the best application usage was 65% peak usage (the theoretical peak which assumes that the processor always has data to crunch and no branches) and the average was 30% of theoretical peak. By contrast, typical fluid-like codes on current U.S. machines typically get less than 10% of peak usage if they have any type of implicitness (currently the magnetohydrodynamics code I use gives about 6% usage on an IBM SP that is #5 on the Top 500 supercomputer list).

I get tired of seeing figures that compare peak flop rates and then don't mention that actually code usage isn't keeping up at all. The Japanese (and Europeans who are allowed to buy NEC machines) are absolutely spanking the US when it comes to fluid codes (for climate modeling for example) and it is largely because they are using vector machines with their old highly optimized Fortran (or High Performance Fortran) codes. The MPP revolution in the U.S. has been manna for the CompSci community, but has set the computational physics community back by 10 years (except for those lucky bastards with embarrassingly parallel jobs).

I would give up an unnecessary body part for an Earth Simulator.

Re:The motivation is a tad depressing

[Pharmboy]

It took Sputnik to kickstart our spacemindedness; I for one consider it sad that a "tremendous amount of interest" -- and the funding that comes with it -- in high-performance computing seems only to have arisen/regenerated with the influence of competitive international politics. Are we really so hardly advanced that our respective national egos are still the driving force behind enthusiasm, financial or otherwise, in certain areas of science?

I don't really see that as bad. Yes, it may look like pure ego, but the space race gave us so much that filtered into the commercial/private sector. From advanced computers to Velcro(tm). From my perspective, being the most advanced nation in as many areas as possible is a good defense, both economically and in a homeland security sense.

Frankly, I don't want the fastest computer chips on the desktop to be designed by a company in another country (even if Intel makes them outside of the US) and I would rather that the cutting edge, be cut here, in my native country. I am sure other people in other countries feel the same, that pushed all of us to new heights. In the end, the technologies are shared anyway. Most anyone in the world can buy Intel chips, for example.

If no one cared who could race a bicycle the fastest, Lance Armstrong would be just some guy who had cancer. Instead, our desire to compete and excell and outdo our neighbors has benefited EVERYONE a great deal. It can bring out the bad side from time to time, but the benefits far outweigh the costs. This urge to compete and win is not unique to America by any means, it is part of being human: man the animal.

I say bring on the computer chip wars: Lets all compete, Japanese, Americans, Europeans, Russians, come one come all. In the end, we will all benefit, no matter who has the bragging rights for a day.