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Parallel Processing For Cardiac Simulations Using an Xbox 360
Foot-in-Mouth writes "Physorg has an article about a researcher, Dr. Simon Scarle at the University of Warwick's WMG Digital Laboratory, who needed to model some cardiological processes. Conventionally, he would requisition time on a university parallel-processing computer or use a network of PCs. However, Dr. Scarle's work history included gaming industry experience as a software engineer at a company associated with Microsoft Games Studio. His idea was that researchers could use Xbox 360s as an inexpensive parallel computing platform due to the console's hefty parallel processing-enabled GPU. He said, 'Although major reworking of any previous code framework is required, the Xbox 360 is a very easy platform to develop for and this cost can easily be outweighed by the benefits in gained computational power and speed, as well as the relative ease of visualization of the system.'"
Because "Dr. Scarle's work history included gaming industry experience as a software engineer at a company associated with Microsoft Games Studio."
ie he's had experience in programming for the platform, was likely used to using Visual Studio with XNA and likely had all the tools he needed to program for the 360 already.
How would this work? Does Microsoft sell licenses for such purposes? Would they need to buy special development boxes instead of cheap of the self hardware? Has the Xbox360 been hacked enough to make this practical?
And most important of all: Why use a Xbox360 GPU in the first place? Aren't there PC GPUs that could run circles around what is in the Xbox360? Wouldn't a PS3 be better suited duo to being an open platform (well, at least as long as the old models are still available)?
He should've used something like CUDA instead, for long term gains. This would have shown far better performance than the Xbox's GPU (which is quite dated now), and easy scalability as better GPUs keep coming to the market. His familiarity with Xbox programming might have enabled him to come up to speed with CUDA quickly.
Well, since the introduction of CUDA by Nvidia, using GPUs for accelerated physical simulations has started to catch on. I've heard of people using PS3 and XBox occasionally, but usually for this sort of work, they'll take a half-dozen or so GeForce cards and use CUDA to parallelize the code. I'm not too familiar with all the ins and outs myself, but as a part of the chemistry community, I get to see a lot of neat applications of the stuff.
If you program C# Windows / Direct3D, programming, XNA for XBOX is easy to program for. You can actually start with XNA on the PC and most stuff will transfer over with minimal changes. You have access to the GPU and shader programming so GPGPU programming ideas can be ported as well.
The PS3 Linux is significantly more difficult to program for, has a different memory model (and programming architecture) for the SPU's, has very poor (compared to Visual Studio) debugging and programming IDE environment, etc. Not to mention that the latest version of the PS3 doesn't even support Linux. There is no GPU access so GPGPU algorithms available on the PC need to be manually ported to the PS3.
That said, if they actually did buy older PS3's, take the steep learning curve to SPU programming, port all of their code to a 100% custom platform with hard-to-use tools, and heavily optimize the SPU code, they would probably be running their algorithms significantly faster on PS3 SPU's than on the XBOX 360 GPU.
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Actually, the case could easily be made that programming a GPU that was NOT meant for general-purpose computing is quite a bit harder than the Cell, which WAS designed with more general-purpose computing in mind. You don't need to port everything required for GPGPU, you just use the libraries and tools developed by IBM for the Cell.
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Because it's really a publicity stunt from Microsoft trying to get the Xbox360 in the forefront of peoples minds in the lead up to Christmas.
The article reads like most of the marketing cover I see from Microsoft (and for that matter most other software companies).
Organisation X needed to do Y but the competing product was too expensive (in price/effort/time). Our product does Y at a fraction of the price/time/effort of our competitor.
The people at Orgaisation X are smart people who know all about Y and are very happy with our product.
Perhaps. Depends on how many nodes he had to set up.
Let's do a bit of "napkin math" on this:
I believe there's 48 unified shader cores in the 360's GPU. That's a nice amount.
There's 112 shader cores in the 9800GT. With the SLI setup, that's 224 of them at your disposal to do GPGPU thread processing with.
Now...done right (meaning not going overboard on the CPU, etc...), you can field a machine for about $600 or so that has an inexpensive SLI board, case, memory, etc. If you're doing a cluster node, you wouldn't need a disk, etc. so you could shave a bit more than you'd think off the price past the first machine bought.
$200 versus $600. The price is compelling. But, unfortunately, you're talking about a machine that's nearly 5 times more powerful (Possibly more, I'm not doing apples-to-apples comparisons on the shader cores...) at this sort of task with the PC- for only about 3 times the cost. To gain the same performance level, you would have to field 5 360's per each PC compute node. If you only need the power of two or three of the 360 nodes, then it makes some sense to do it with that, especially if you're familiar with the environment (the gent we're talking about in the threads here was that...).The power consumption will be comparable across the board, so that's not so much a consideration.
Where it really hits the wall is with the cluster fabric itself. Using PS3's and 360's is "cool" but it's actually not overly practical past about 10 or so machines for most performance computing applications because of the limitation of the cluster interconnect you have at your disposal. With those machines you will be limited to 1Gb Ethernet which limits your interconnect performance to about 750Mbits per node. When you go to match the performance of the PC box, you will find that you can do it, but it'll take 5 or so 360's to do it because of the overhead, lower performing hardware, and all. You'll have difficulty matching a cluster of the same numbers of PC's- and we won't get into using Myrinet, Infiniband, or iWarp channel adapters for 10Gb interconnects on the PC's which will make it be basically a huge SMP machine for all intents and purposes until you scale it to about 32 or so machines.
I think the assessment that it's familiarity and "cool" factor that drove this decision- not price or actual usefulness.
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Sony just canned the PS3 Linux install option. :)
I doubt he's using JUST the GPU. The 3x3.2GHz PowerPC processors in the Xbox 360 are pretty compelling. The PS3 MIGHT have more raw power but you're not actually even allowed to use its GPU unless you have first-string developer status. Scientific computing on the PS3 focuses on the Cell, and it seems like there's an awful lot of unuseful hardware wrapped around it.
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