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With Linux Clusters, Seeing Is Believing

Posted by Hemos on Mon Dec 13, 2004 11:41 AM
from the believing-is-truth dept.
Roland Piquepaille writes "As the recent release of the last Top500 list reminded us last month, the most powerful computers now are reaching speeds of dozens of teraflops. When these machines run a nuclear simulation or a global climate model for days or weeks, they produce datasets of tens of terabytes. How to visualize, analyze and understand such massive amounts of data? The answer is now obvious: using Linux clusters. In this very long article, "From Seeing to Understanding," Science & Technology Review looks at the technologies used at Lawrence Livermore National Laboratory (LLNL), which will host the IBM's BlueGene/L next year. Visualization will be handled by a 128- or 256-node Linux cluster. Each node contains two processors sharing one graphic card. Meanwhile, the EVEREST built by Oak Ridge National Laboratory (ORNL), has a 35 million pixels screen piloted by a 14-node dual Opteron cluster sending images to 27 projectors. Now that Linux superclusters have almost swallowed the high-end scientific computing market, they're building momentum in the high-end visualization one. The article linked above is 9-page long when printed and contains tons of information. This overview is more focusing on the hardware deployed at these two labs."
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  • by Vvornth (828734) on Monday December 13 2004, @11:43AM (#11073002) Homepage
    This is how we nerds measure our penises. ;)
  • by daveschroeder (516195) * on Monday December 13 2004, @11:43AM (#11073008)
    Virginia Tech's "System X" cluster cost a total of $6M for the asset alone (i.e., not including buildings, infrastructure, etc.), for performance of 12.25 Tflops.

    By contrast, NCSA's surprise entry in November 2003's list, Tungsten, achieved 9.82 Tflops for $12M asset cost.

    Double the cost, for a Top 100 supercomputer's-worth lower performance.

    And it wasn't because Virginia Tech had "free student labor": it doesn't take $6M in labor to assemble a cluster. Even if we give it an extremely, horrendously liberal $1M for systems integration and installation, System X is still ridiculously cheaper.

    I know there will be a dozen predictable responses to this, deriding System X, Virginia Tech, Apple, Mac OS X, linpack, Top 500, and coming up with one excuse after another. But won't anyone consider the possibility that these Mac OS X clusters are worth something?
    • by Spy Hunter (317220) on Monday December 13 2004, @12:15PM (#11073293) Journal
      I think you missed something here in your rush to defend Apple. The article is not about building high-teraflop supercomputers; it is about using small-to-medium sized clusters of commodity hardware to run high-end visualization systems (with Linux's help of course). Since they specifically want top-of-the-line graphics cards in these machines, Macs would not be the best choice. PCs have PCI express now (important for nontraditional uses of programmable graphics cards, as these guys are probably doing) and the latest from ATI/NVidia is always out first on PCs, cheaper.
    • by zapp (201236) on Monday December 13 2004, @12:15PM (#11073296)
      G5 nodes do have excellent performance, but don't assume OSX is all they can run.

      We at Terra Soft have just released Y-HPC, our version of Yellow Dog Linux, with a full 64-bit development environment, and a bunch of cluster tools built in.

      I'm not much of a marketting drone, but being as I am part of the Y-HPC team, I had to put a shameless plug in. Bottom line is, it kicks OSX's ass any 2 ways you look at it.

      Y-HPC [terrasoftsolutions.com]
      • Truly no offense intended, but...

        I've tried installing YDL on a small G5 cluster. It was a PITA to get running (3 installs before I was able to get the X server running right). And still I can't find any fan control. After 5 minutes the fans spool up to "ludicrous speed" and stick there.

        I really want to like YDL. I've been talking to the folks who do OSCAR about trying to get OSCAR to support YDL. But I'm not sure how it will work out yet, at least until I can figure out how to turn down the fans!

        • by zapp (201236) on Monday December 13 2004, @01:05PM (#11073764)
          YDL is not intended to run on a G5 cluster, unless you had Y-HPC. YDL on its own is only 32-bit.

          Fan control was integrated into the kernel over a month ago, and is most definitelly in the first version we released last week.

          We have also developed a nice pretty installer for the head node in a cluster, and wrote Y-Imager (front end for Argonne's System Imager), to automate the building of compute nodes in a cluster.

          No offense taken :)
    • by RazzleFrog (537054) <mike.thinckaloud@com> on Monday December 13 2004, @12:19PM (#11073333)
      Beside the fact that you are (please forgive me) Apples and Oranges, your sample size is way too small to use as conclusive evidence. Until we start seeing X Serve Clusters in a few more places we can't be sure of the cost benefit.
    • by RealAlaskan (576404) on Monday December 13 2004, @12:19PM (#11073334) Homepage Journal
      Virginia Tech's "System X" cluster cost a total of $6M for the asset alone (i.e., not including buildings, infrastructure, etc.), for performance of 12.25 Tflops.

      By contrast, NCSA's surprise entry in November 2003's list, Tungsten, achieved 9.82 Tflops for $12M asset cost.

      When I looked here [uiuc.edu], I found this: ``Tungsten entered production mode in Novermber 2003 and has a peak performance of 15.36 teraflops (15.36 trillion calculations per second).''

      To me, that looks faster than System X, not slower.

      Let's see: NCSA stands for ``National Center for Supercomputing Applications''. ``NCSA [uiuc.edu] is a key partner in the National Science Foundation's TeraGrid project, a $100-million effort to offer researchers remote access ...''

      Looks as if the NCSA has a huge budget. I'd guess that ``gold-plated everything'' and ``leave no dollars unspent'' are basic specs for everythig they buy.

      What can we learn about Virginia Tech? How about this [vt.edu]:

      System X was conceived in February 2003 by a team of Virginia Tech faculty and administrators and represents what can happen when the academic and IT organizations collaborate.

      Working closely with vendor partners, the Terascale Core Team went from drawing board to reality in little more than 90 days! Building renovations, custom racks, and a lot of volunteer labor had to be organized and managed in a very tight timeline.

      In addition to the volunteer labor, I'd guess that Virginia Tech had very different design goals, in which price was a factor. NCSA's bureaucracy probably accounted for a lot of those extra $6M they spent. Different designs and goals probably had a lot to do with the rest of the price, but I suspect that a bureaucratic procurement process was the main cause for the higher price of the Xeon system.

      Yes, System X and the Apple hardware is pretty neat, but don't use the price/performance ratio of these two systems as a metric for the relative worth of Linux and OSX clusters.

      It's unfair and meaningless to compare volunteer labor and academic pricing and scrounging on a limited budget to bureaucratic design, bureaucratic procurement and an unlimited budget.

      • Rpeak, not Rmax (Score:5, Insightful)

        by daveschroeder (516195) * on Monday December 13 2004, @12:29PM (#11073427)
        Look here [top500.org].

        The speed you quoted is the theoretical peak, not the actual maximum achieved in a real world calculation (like the Top 500 organization's use of Linpack).

        System X's equivalent theoretical peak is 20.24 TFlops.

        I'm also not indicting Linux clusters in the least; they've clearly shown they can outperform traditionally architected and constructed supercomputers for many tasks, with the benefit of using commodity parts - at commodity pricing. All I'm saying is that there's a new player here, and it's a real contender, and has done a lot for very little money...which was the whole goal of Linux clusters in this realm in the first place.

        (Also, as I said, the volunteer labor model is irrelevant - let's just pretend it was professionally installed for an additional $1M, or even $2M if that would satisfy you. It's still several million dollars cheaper, and 3Tflops greater performance. These are BOTH rackmount clusters with similar amounts of nodes and processors, running a commodity OS with fast interconnects. There are differences, yes, and perhaps even differences in goals. But looking past that, price/performance for something like this is still an important metric.)
    • You have to take the costs with a grain of salt. They built the original machine for $5.2M. They then upgraded all the nodes from PowerMac G5s to Xserve G5s for $600K. Even if you assume that the $5.2 was a fair price for their original system, the upgrade price was an absolute gift from Apple. The cost per node to upgrade was about $550. Since they moved from non-ECC RAM to ECC RAM (4GB/node), the memory upgrade should have cost more than that alone.

      Vendors will often give away hardware in order to
    • by hackstraw (262471) * on Monday December 13 2004, @01:51PM (#11074275) Homepage
      I know there will be a dozen predictable responses to this, deriding System X, Virginia Tech, Apple, Mac OS X, linpack, Top 500, and coming up with one excuse after another. But won't anyone consider the possibility that these Mac OS X clusters are worth something?

      Your right!

      1st, System X or the "Big Mac" was thrown together so that people like us would talk about it and to get a good standing for the November 2003 top 500 list. They did an excellent job at this.

      Now for some reality. The system is not yet operational.

      When it was first thown together, everyone "in the know" and myself questioned how this was going to work without a reliable memory subsystem, and the VT people responded that they were going to write software to correct any hardware errors, and we said OK, whatever. Then, they said, hmm, we kinda needa a reliable memory subsystem, so lets rip out all 1,100+ machines and start over with these new Xserve boxes that have ECC memory in them.

      This system has not come up yet with the new Xserves, according to their website [vt.edu].

      Now, I'm going to make a comment on Linpack. Linpack, like all good benchmarks are really good at measuring that benchmark's performance. Linpack is a good benchmark, but it is also a benchmark that does not require much RAM per node to run. Some applications do need a good amount of RAM/node to run and being that RAM costs $$, the cost adds up very quickly, and the cost/cpu/teraflop goes down accordingly.

      With the comparison between System X and Tungsten NCSA cluster. Personally, I don't know why the Tungsten cluster cost more because the Mac cluster has more RAM/node and each node should have been cheaper in general. The NCSA cluster uses Myrinet which I know is expensive, but I do not know that in comparison to the Infiniband equipment on the Macs. Supposedly, the Infiniband interconnects were what got System X on the top500 list with such good results, or at least that is what the head of the project told me.

      Although its popular here on slashdot because many of the readers are younger and inexperienced (and have no money) that they praise anything that costs less and extra brownie points go towards an underdog like AMD or Linux, however in the real world people actually will pay extra for something to ensure that it works. Working equipment may seem superfluous to the dorm room Linux guru, but trust me, I know what its like to work with equipment that cost about $1 mil and it doesn't work. We could have gone with the 2nd bidder at $1.2 mil and it would have worked. Yes, we "saved" $200,000, but we also wasted well over $500,000 when one considers that over 50% of the equipment is faulty and many people's time has been wasted.
      • by daveschroeder (516195) * on Monday December 13 2004, @12:38PM (#11073504)
        ...except get untold amounts of recognition, publicity, free advertising, news articles, and the capability to catapult themselves to the forefront of the supercomputing community overnight for a paltry sum of money, thus attracting millions of dollars of additional funding and grants to build clusters that WILL be doing real work, such as the one we're talking about now (which is more than capable now that it has ECC memory), and the several additional clusters they plan to build in the future, not to mention the benefit of proving that a new architecture, interconnect, and OS will perform well as a supercomputer, allowing more choice, competition, and innovation to enter the scene, which ultimately results in more and better choices for everyone.
  • by Anonymous Coward
    How to visualize, analyze and understand such massive amounts of data?

    How to write complete sentences?
  • by BuddieFox (771947) on Monday December 13 2004, @11:44AM (#11073010)
    The article linked above is 9-page long when printed and contains tons of information.

    I hope the poster doesn't actually expect any of us to post any meaningful comments based on having read that article, it's a lost cause.. At least on me.
  • by HarveyBirdman (627248) on Monday December 13 2004, @11:45AM (#11073025) Journal
    The article linked above is 9-page long when printed and contains tons of information.

    Damn! What kind of paper stock are you printing on?

  • by Anonymous Coward on Monday December 13 2004, @11:46AM (#11073033)
    Roland Piquepaille and Slashdot: Is there a connection?

    I think most of you are aware of the controversy surrounding regular Slashdot article submitter Roland Piquepaille. For those of you who don't know, please allow me to bring forth all the facts. Roland Piquepaille has an online journal (I refuse to use the word "blog") located at www.primidi.com [primidi.com]. It is titled "Roland Piquepaille's Technology Trends". It consists almost entirely of content, both text and pictures, taken from reputable news websites and online technical journals. He does give credit to the other websites, but it wasn't always so. Only after many complaints were raised by the Slashdot readership did he start giving credit where credit was due. However, this is not what the controversy is about.

    Roland Piquepaille's Technology Trends serves online advertisements through a service called Blogads, located at www.blogads.com. Blogads is not your traditional online advertiser; rather than base payments on click-throughs, Blogads pays a flat fee based on the level of traffic your online journal generates. This way Blogads can guarantee that an advertisement on a particular online journal will reach a particular number of users. So advertisements on high traffic online journals are appropriately more expensive to buy, but the advertisement is guaranteed to be seen by a large amount of people. This, in turn, encourages people like Roland Piquepaille to try their best to increase traffic to their journals in order to increase the going rates for advertisements on their web pages. But advertisers do have some flexibility. Blogads serves two classes of advertisements. The premium ad space that is seen at the top of the web page by all viewers is reserved for "Special Advertisers"; it holds only one advertisement. The secondary ad space is located near the bottom half of the page, so that the user must scroll down the window to see it. This space can contain up to four advertisements and is reserved for regular advertisers, or just "Advertisers". Visit Roland Piquepaille's Technology Trends (www.primidi.com [primidi.com]) to see it for yourself.

    Before we talk about money, let's talk about the service that Roland Piquepaille provides in his journal. He goes out and looks for interesting articles about new and emerging technologies. He provides a very brief overview of the articles, then copies a few choice paragraphs and the occasional picture from each article and puts them up on his web page. Finally, he adds a minimal amount of original content between the copied-and-pasted text in an effort to make the journal entry coherent and appear to add value to the original articles. Nothing more, nothing less.

    Now let's talk about money. Visit http://www.blogads.com/order_html?adstrip_category =tech&politics= [blogads.com] to check the following facts for yourself. As of today, December XX 2004, the going rate for the premium advertisement space on Roland Piquepaille's Technology Trends is $375 for one month. One of the four standard advertisements costs $150 for one month. So, the maximum advertising space brings in $375 x 1 + $150 x 4 = $975 for one month. Obviously not all $975 will go directly to Roland Piquepaille, as Blogads gets a portion of that as a service fee, but he will receive the majority of it. According to the FAQ [blogads.com], Blogads takes 20%. So Roland Piquepaille gets 80% of $975, a maximum of $780 each month. www.primidi.com is hosted by clara.net (look it up at http://www.networksolutions.com/en_US/whois/index. jhtml [networksolutions.com]). Browsing clara.net's hosting solutions, the most expensive hosting service is their Clarahost Advanced (http://ww [clara.net]
  • Wow! (Score:3, Funny)

    by Anonymous Coward on Monday December 13 2004, @11:46AM (#11073034)
    Supercomputers have become so advanced we need more supercomputers just to understand them.
    • At the risk of being called off topic.

      When Harlie was one [amazon.com] was the first book that I recall about a computer that designed another more complex computer that only it could understand.

      Maybe Harlie was a Linux cluster.

    • Wait until supercomuters become so complex that we need supercomputers to design the supercomputers which we need to understand the output of the supercomputer. Problem is, to understand the supercomputer-designing supercomputer's output we need a supercomputer to be designed by a supercomputer ... ok, there's a way out: Let the supercomputer build the supercomputer it designed.
      Ok, now we just need another supercomputer to test the supercomputer the supercomputer built us to interpret the output of the supe
  • A 35 million pixel screen would rock for Half-Life 2. Where can I get me one? Looking at the picture, it's kind of like 3 monitors stuck together, so maybe I'll save some money and only get 1/3rd of the setup. How much can that cost? I mean, really.
    • A 35 million pixel screen would rock for Half-Life 2. Where can I get me one? Looking at the picture, it's kind of like 3 monitors stuck together, so maybe I'll save some money and only get 1/3rd of the setup. How much can that cost? I mean, really.

      I know you're joking, but since I'm the hardware architect for the LLNL viz effort, I'll bite anyway. :-)

      Here's what you'll need at minimum:

      • A lot of display devices (monitors, projectors, whatever)
      • Sufficient video cards to drive the above (with new ca
  • by weeboo0104 (644849) on Monday December 13 2004, @11:52AM (#11073102) Journal
    With Linux Clusters, Seeing Is Believing

    Does this mean that we don't have to just imagine a Beowulf cluster anymore?
  • Finally.... (Score:3, Funny)

    by ElvenMonkey (789317) on Monday December 13 2004, @11:53AM (#11073111)
    A machine that can compile a Stage1 Gentoo install in a reasonable amount of time.
    • Unless you change the settings so it is compiling mulible applications at the same time. The speed to install Stage 1 of Gentoo won't be much faster then a 2 maybe 4 CPU system. These super computers and clusters use a concept called Parallel Processing. It is a process where a task is broken up and are handled by many processors in parallel. Most applications are not designed to run in parallel. So unless you have a compiler that is designed with Parallel Processing the OS will give the compiling task to
  • by Anonymous Coward on Monday December 13 2004, @11:57AM (#11073152)
    So, if I've got this straight, Slashdot drives the banner ad traffic, real journalists write the content, and all Roland has to do is rip off a few articles, then sit in the middle and collect the checks. How do I get a sweet gig like that?
  • by roxtar (795844) on Monday December 13 2004, @12:08PM (#11073233) Homepage Journal
    To reaffirm what the article said building linux clusters is very simple. In fact certain distributions such as bccd [uni.edu] and cluster knoppix [bofh.be] specifically for that. Although configuring clustering softwares such as pvm mpi lam mosix etc wouldn't be a problem, I prefer something which has almost everything build into one package thats why I like the above distros. In fact I built a cluster (using BCCD) at home and used it to render images built from povray [povray.org]. I used pvmpov [sourceforge.net] for the rendering on a cluster part. Although there were only four machines the speed difference was evident. And above all making clusters is extremely cool and shows the paradigm shift towards parallel computing.
    • by LithiumX (717017) on Monday December 13 2004, @12:20PM (#11073344)
      I do think clusters are going to be a dominant architecture for the next few decades, but I also think the current ultra-heavy emphasis on clusters is as much a function of asymptotic limitations as much as the natural evolution of the technology. It's currently cheaper to build a cluster out of a whole mess of weaker processors than it is to develop a single ubercore. I doubt that situation will last more than a decade, though, going by previous history.

      Computers were initially monolithic machines that effectively had a single core. By the 70's, the processing on many mainframes had branched out so that a single mainframe was often a number of seperate systems integrated into a whole (though nothing on the level we see today). By the 80's it seemed to swing back to monolithic designs (standalone pc's, ubercomputer Crays) and it wasn't until the 90's that dual and quad processing became commonplace (though the technology had existed before).

      Eventually, someone will hit on a revolutionary new technology (sort of like how transistors, IC's, and microprocessors were revoloutionary) that renders current LVSI systems obsolete (optical? quantum?), and the cost/power ratio will shift dramatically, making it more economical to go back to singular (and more expensive) powerful cores rather than cheap (but weaker) distributed cores.
      • But on the other hand problems which require immense amount of calculations will exist and I don't see how advances in VLSI or some other technology will eliminate these kind of problems. So what I actually believe is that to some extent, yes we may go back to singular cores but imagine the power of those single cores together. In my opinion even if new technology does arrive, clusters are here to stay.
  • very long article... (Score:4, Interesting)

    by veg_all (22581) on Monday December 13 2004, @12:08PM (#11073238)
    So now Monsieur Piquepaille has been shamed by scornful posters [tinyurl.com] into including a link to the actual article (instead of harvesting page views), but he'd still really, really like you to click through to his page....
  • Really... (Score:5, Insightful)

    by grahamsz (150076) on Monday December 13 2004, @12:09PM (#11073249) Homepage Journal
    Now that Linux superclusters have almost swallowed the high-end scientific computing market...

    While some simulations parallelize very well to cluster environments, there are still plenty tasks that don't split up like that.

    The reason clusters make up a lot of the Top 500 list is that they are relatively cheap and you can make them faster by adding more nodes - whereas traditional supercomputers need to be deisgned from the ground up.
  • Maybe they are building cool Linux clusters but they can't be that smart. They have their mail addresses just sitting here on the site for spammers to harvest!
  • Leave some market share for the big guys.
  • by saha (615847) on Monday December 13 2004, @12:41PM (#11073539)
    Clusters are proven to be cost effective, but they do require more labor to optimize code to get it to work in that environment. Its easier to have the system and the complier do the work for you in a single image system. This article address those issues and concerns. single image shared vs distributed memory in large Linux systems [newsforge.com]
  • by Sai Babu (827212) on Monday December 13 2004, @12:58PM (#11073695) Homepage
    IMO, computer aided visualization is over rated. Sure, it's good in a production environment but the mental effort of visualization is a tremendous aid to imagination. There's no way to computerize epiphany.
  • by LordMyren (15499) on Monday December 13 2004, @02:46PM (#11074860) Homepage
    PCI-E has symmetric bandwidth. Current generation graphics cards will undoubtedly not be able to take advantage of this feature, they've spent so long getting data to the graphics card that thats all they're optimized for, but in the long run this has some crucial implications.

    Namely, it allows for graphics cards to operate better in situations exactly like this; clustered applications. As it stands, the graphics card can crunch an enormous amount of data, but is extremely poor at sending it back to the CPU & system. It's optimized for screen dumping only.

    Sony's Cell is going to be absolutely crucial as a tech demo for this foresighted technology. We're heading towards a more distributed computer architecture where various specialized units pipe data between each other.

    In summation,
    Its my hope that eventually graphics cards will catch up and perform better bi-directionally. After that, we've got to wait another 5 years for PCI-E implementations to catch up and perform better switching (vis-a-vise multiple fully-switched x16 busses). We are moving away from the CPU for high performance computing; the cpu currently performs both control and data-processing. Graphics cards are just the first wave of the distributed architecture phenomena, Cell will be a light-year jump towards the future of computing in the intricate levels of hardware reconfigurability. there's a good powerpoint on the patents behind cell here [unc.edu].

    Ultimately this will lead towards the tearing down of the computer as a monolithic device, and a rethinking of what exactly the network and os's roles are. Queue exo-kernel and DragonFly BSD debates.
  • by totallygeek (263191) on Monday December 13 2004, @04:32PM (#11075961) Homepage
    Why does the scientific community keep using Linux? Everyone knows now that Microsoft [googlesyndication.com] has a lower TCO and is better at everything [slashdot.org].