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Big Mac Benchmark Drops to 7.4 TFlops
coolmacdude writes "Well it seems that the early estimates were a bit overzealous. According to preliminary test results (in postscript format) on the full range of CPUs at Virginia Tech, the Rmax score on Linpack comes in at around 7.4 TFlops. This puts it at number four on the Top 500 List. It also represents an efficiency of about 44 percent, down from the previous result of 80 achieved on a subset of the computers. Perhaps in light of this, apparantly VT is now planning to devote an additional two months to improve the stability and efficiency of the system before any research can begin. While these numbers will no doubt come as a disappointment for Mac zealots who wanted to blow away all the Intel machines, it should still be noted that this is the best price/performance ratio ever achieved on a supercomputer. In addition, the project was successful at meeting VT's goal of developing an inexpensive top 5 machine. The results have also been posted at Ars Technica's openforum."
I've always been sort of intrigued by
Quod scripsi, scripsi.
Way to go /. -- updated the logo from G4 to G5 just in time.
--
First, from a an Oct 22 New York Times story:
Officials at the school said that they were still finalizing their results and that the final speed number might be significantly higher.
This will likely be the case.
Second, they're only 0.224 Tflops away from the only Intel-based cluster above it. So saying "all the Intel machines" in the story is kind of inaccurate, as if there are all kinds of Intel-based clusters that will still be faster; there is only one Intel-based cluster above it, and with only preliminary numbers for the Virgina Tech cluster at that.
Third, this figure is with around 2112 processors, not the full 2200 processors. With all 1100 nodes, even with no efficiency gain, it will be number 3, as-is.
Finally, this is the a cluster of several firsts:
First major cluster with PowerPC 970
First major cluster with Apple hardware
First major cluster with Infiniband
First major cluster with Mac OS X (Yes, it is running Mac OS X 10.2.7, NOT Linux or Panther [yet])
Linux on Intel has been at this for years. This cluster was assembled in 3 months. There is no reason for the Virginia Tech cluster to remain at ~40% efficiency. It is more than reasonable to expect higher than 50%.
It's still destined for number 3, and its performance will likely even climb for the next Top 500 list as the cluster is optimized. The final results will not be officially announced until a session on November 18 at Supercomputing 2003.
What they're not telling you is that the real reason they are building a supercomputer is because the only copy of the router passwords is GPG-encrypted, and they lost the key.
That 80% efficiency simply sounded too good to be true, and it was.
Now its at 44%. Thats not a small drop, thats a MASSIVE drop.
They didnt predict any loss in going from a small subset to the whole system? Or was it a publicity stunt (we can outperform everyone! our names are __________!)
[I can picture a world without war, without hate. I can picture us attacking that world, because they'd never expect it]
That's nothing, last time I benchmarked my Big Mac Cluster (100 Big Macs) it came to almost 57.6 megacalories. Those Apples will never be able to match that!
I read the internet for the articles.
Not terribly surprising. Much like estimated death tolls for disasters, never believe the first set of benchmarks for a computer. Wait until thorough testing can be done before you start believing the numbers.
;)
Y'all should know this by now.
~D
This sig has been enciphered with a one-time pad. It could say almost anything.
"best price performance" and "Apple" in their minds?
"Virginia Tech: Home of the Poor Man's Supercomputer and Michael Vick."
Apparently there are a lot of cases where a MULTIPLY and an ADD do come together like that, but I'm not surprised if LINPACK doesn't consist entirely of those pairs. ;)
The 17.6 TFLOP theoretical peak assumed a perfect case consisting entirely of MULTIPLY-ADD pairs. In a case assuming no MULTIPLY-ADD pairs, the theoretical peak is 8.8 TFLOPs.
7.4 TFLOPs is only 42% of 17.6 TFLOPs, but it's 84% of 8.8 TFLOPs. I suspect the actual "efficiency" of the machine lies somewhere in the middle.
(As for me, I'm happy with just ONE dualie...)
While these numbers will no doubt come as a disappointment for Mac zealots who wanted to blow away all the Intel machines, it should still be noted that this is the best price/performance ratio ever achieved on a supercomputer.
It still bests all other Intel hardware with only the Alpha hardware on top. And given the CPU count, even the Alpha hardware does not match it. Look at the numbers.....The Linux based 2.4Ghz cluster has almost 200 more CPU's on board with a 217 Gflop/sec difference. The Alpha clusters are running anywhere from 1,984 to 6,048 more CPU's.
Visit Jonesblog and say hello.
See http://www.netlib.org/benchmark/performance.pdf page 53.
Since yesterday's release at 7.41 Tflop, the G5 cluster has already increased almost a Tflop, and is now ahead of the current #3 MCR Linux cluster, and about 0.5 Tflop behind a new Itanium 2 cluster.
/Watched WarGames too many times as a kid.
First you have the iTunes store which doesn't do anything but give the average user basically anything he or she might have wanted to have in on online music store. Despite its being free, we're all cheesed off that it doesn't support OGG, or it's meant partly to push iPods (duh), or whatever.
Now this -- a supercomputer that has, to quote that again, the "best price/performance ratio ever achieved on a supercomputer." But dang it all, it doesn't completely blow away every established precedent -- it's just in the top five on the usual list of comparisons. One more crushing disappointment.
From Microsoft, we just want products that don't completely ream us. From Apple, we want the entire world to seem a little friendlier and cooler with every product release, every dot-incremenent OS update. They both disappoint us, but the expectations seem a little different...
"Fundamentalism" isn't about divine morality. It's about human authority.
The preliminary performance report at http://www.netlib.org/benchmark/performance.pdf contains the new entries for the upcoming list as well (see page 53).
Anyone know how much merit there is to using Nmax (or N1/2) to compare different systems?
"There are a dozen opinions on a matter until you know the truth. Then there is only one." - CS Lewis (paraprhase)
Yes, but doesn't Moore's Law and the commodification of computer hardware suggest that each new generation supercomputer will have the best price/performance ratio?
I installed a button on the front of my cluster
to manually clock the CPU's.
So far i've managed ONE whole flop.
My record is for the slowest supercomputer
on the planet.
siggy played guitar
Jack Dongarra says that a "supercomputer" is simply a computer that, for todays's standards, is REALLY fast. I saw one presentation from him, and he said he run the Linpack benchmark on his notebook (2.4 GHz Pentium 4) and it would get to the bottom of the Top500 list in 1992. So, this supercomputer definition is very fluid.
Because the Power4 is hotter and uses more current than the G5. To use 2200 Power 4 CPUs they would have to about triple the cooling capacity of the room. For all the heat and power, the Power4 lacks the AltiVec units that allow the G4/G5 to process vector operations so quickly.
The G5 is also significantly lower cost than the Power4
Article X: The powers not delegated... by the Constitution...are reserved...to the people
The degree of loss is interesting, and suggests that their algorithm for distributing work needs tightening up on the high-end. Nonetheless, none of these are bad figures. When this story first broke, you'll recall the quote from the top500 list maintainer who pointed out that very few machines had high performance ratings, when they got into the large numbers of nodes.
I'd say these are extremely credible results, well worth the project team congratulating themselves. If the team could open-source the distribution algorithms, it would be interesting to take a look. I'm sure plenty of Mosix and BProc fans would love to know how to ramp the scaling up.
(The problem of scaling is why jokes about making a Beowulf cluster of these would be just dumb. At the rate at which performance is lost, two Big Macs linked in a cluster would run slower than a single Big Mac. A large cluster would run slower than any of the nodes within it. Such is the Curse that Amdahl inflicted upon the superscaler world.)
The problem of producing superscalar architectures is non-trivial. It's also NP-complete, which means there isn't a single solution which will fit all situations, or even a way to trivially derive a solution for any given situation. You've got to make an educated guess, see what happens, and then make a better informed educated guess. Repeat until bored, funding is cut, the world ends, or you reach a result you like.
This is why it's so valuable to know how this team managed such a good performance in their first test. Knowing how to build high-performing clusters is extremely valuable. I think it not unreasonable to say that 99% of the money in supercomputing goes into researching how to squeeze a bit more speed out of reconfiguring. It's cheaper to do a bit of rewiring than to build a complete machine, so it's a lot more attractive.
On the flip-side, if superscaling ever becomes something mere mortals can actively make use of, understand, and refine, we can expect to see vastly superior - and cheaper - SMP technology, vastly more powerful PCs, and a continuation of the erosion of the differences between micros, minis, mainframes and supercomputers.
It will also make packing the car easier. (* This is actually a related NP-complete problem. If you can "solve" one, you can solve the other.)
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
I think that magazine article must be wrong. If 1100 Macs use as much power as 3000 homes, then each mac is using about 3 houses worth of power. That seems excessive unless the home is in a 3rd world country or those 9 fans are really really running full blast. More likely, each G5 (with networking and cooling equipment) uses a few hundred watts. Even at 500 W/Mac, 1100 Macs, $0.15/kWH, 24 Hr/day, 365 day/year the cluster costs about $722,700/year. More likely, each Mac probably only consumes an average of 300 W max and is not running full tilt 24x7, so the cost is maybe around $300-$400k/year.
But your point is a good one. I often wonder about the environmental economics of people running SETI, Folding@Home, etc. on older machines. Most of those older "spare" CPU-cycles are quite costly in terms of electricity relative to newer faster machines that do an order of magnitude more computing with the same amount of electricity.
Two wrongs don't make a right, but three lefts do.
My feeling is that the ~40% efficiency seen on the larger scale run is an indication that either VA Tech spent very little time tuning the problem size or they didn't design their InfiniBand fabric to really handle 1100 nodes hammering away at Parallel Linpack. (Given that they've been extremely vague about how their IB network is structured, I fear it may be the latter.)
I doubt that's true, especially if they're using the IBM PPC compilers. The G4 has both significantly less memory bandwidth and a single double-precision-capable FPU, whereas the G5 is basically a single-core Power4 with an AltiVec unit in place of some cache. IBM's compilers (despite being a little wonky as far as naming and argument syntax) generally produce pretty fast code."My life's work has been to prompt others... and be forgotten." --Cyrano de Bergerac
The 21st version of this list does not
show the SETI@Home project. The top entry
is NEC at 35 terraflops. Today's SETI@Home
average for the last 24 hours is 61 terraflops.
It may be a virtual supercomputer, but it
is producing real results.
-- Stephen.
KASY0 achieved 187.3 GFLOPS on the 64-bit floating point version of HPL, the same benchmark used on "Big Mac". While "Big Mac" is about 40 times faster on that benchmark, it is about 130 times the cost of KASY0 (~$40K vs ~$5200K). Considering the size difference, "Big Mac" is VERY impressive, but it can't claim to be the best price/performance supercomputer on the HPL benchmark.
Note: KASY0 gets 482.6 GFLOPS (0.48 TFLOPS) on a 32-bit precision version of Linpack, satisfying our under $100 per GFLOPS claim.
Regardless, Virginia Tech's "Big Mac" is a very impressive machine. My congratulations to them!
Tim Mattox