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Intel

Intel Reveals More Larrabee Architecture Details 123

Posted by CmdrTaco
from the switching-from-binary-to-trinary dept.
Ninjakicks writes "Intel is presenting a paper at the SIGGRAPH 2008 industry conference in Los Angeles on Aug. 12 that describes features and capabilities of its first-ever forthcoming many-core architecture, codenamed Larrabee. Details unveiled in the SIGGRAPH paper include a new approach to the software rendering 3-D pipeline, a many-core programming model and performance analysis for several applications. Initial product implementations of the Larrabee architecture will target discrete graphics applications, support DirectX and OpenGL, and run existing games and programs. Additionally, a broad potential range of highly parallel applications including scientific and engineering software will benefit from the Larrabee native C/C++ programming model."
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Intel Reveals More Larrabee Architecture Details

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  • Re:Good old SIGGRAPH (Score:5, Informative)

    by TheRaven64 (641858) on Monday August 04, 2008 @09:09AM (#24465317) Journal
    Unlike, say, any other academic conference where exactly the same thing happens. People don't go to SIGGRAPH for the sake of it, they go because it's the ACM Special Interest Group on GRAPHics main conference and getting a paper accepted there gets people in the graphics field a lot of respect. Many of the other ACM SIG* conferences are similar, and most other academic conferences are similar in form, but typically smaller.
  • Re:Good news (Score:5, Informative)

    by gnasher719 (869701) on Monday August 04, 2008 @09:15AM (#24465403)

    I think it depends on how much Larrabee will cost, however with what we know so far Apple seems to be heading into multi-CPU architectures, so using Larrabee would make sense.

    Larrabee costs somewhere between 150 and 300 Watt, so MacBooks and Mac Minis are not likely to use them. Mac Pro, on the other hand, possibly.

  • by Anonymous Coward on Monday August 04, 2008 @09:16AM (#24465411)

    No, because the article is about Intel explaining that the purpose of Larrabee is NOT to be specialised like that. It's meant to be a completely programmable architecture that you can use for rasterization, ray tracing, folding, superPi or whatever else you want to program onto it.
    Basically, they're trying to say "it's not REALLY a GPU as such, it's actually a really fat, very parallel processor. But you can use it as a GPU if you really want to".

  • by TheRaven64 (641858) on Monday August 04, 2008 @09:16AM (#24465415) Journal

    It almost certainly won't work. In the past, there has been a swing between general and special purpose hardware. General purpose is cheaper, special purpose is faster. When general purpose catches up with 'fast enough' then the special purpose dies. The difference now is that 'cheap' doesn't just mean 'low cost' it also means 'low power consumption,' and special-purpose hardware is always lower power than general-purpose hardware used for the same purpose (and can be turned off completely when not in use).

    If you look at something like TI's ARM cores, they have a fairly simple CPU and a whole load of specialist DSPs and DSP-like parts that can be turned on and off independently.

  • Re:OpenGL (Score:5, Informative)

    by TheRaven64 (641858) on Monday August 04, 2008 @09:21AM (#24465475) Journal
    The Quake engine uses OpenGL (or its own software renderer, but I doubt anyone uses that anymore), so games based on it do use OpenGL. Most open source games that use 3D use it, as do most OS X games, and quite a lot of console games. OpenGL ES is supported on most modern mobile phone handsets (all Symbian handsets, the iPhone and Android) and the PS3. I don't know why you'd think OpenGL was dead or dying - it's basically the only way of writing portable 3D code that you want to benefit from hardware acceleration at the moment.
  • Re:OpenGL (Score:2, Informative)

    by Anonymous Coward on Monday August 04, 2008 @09:39AM (#24465749)

    You still need an API - which OpenGL provides. On the hardware side of things, few chips actually implement the (idealized) state machine that OpenGL specifies, it's always a driver in between that translates the OpenGL model to the chip model.

  • by Mathinker (909784) on Monday August 04, 2008 @10:42AM (#24466671) Journal

    > so far it looks like the x86 version of Cell

    Then you missed the fact that the article says it uses a coherent 2-level cache for inter-core communications; the Cell BE is quite exotic in that it uses DMA transfers and has no memory coherency between the SPEs.

    The article doesn't explicitly state that the Larrabee cores are homogeneous, but I would be surprised if they weren't; the Cell cores are somewhat heterogeneous if you want to use the PowerPC core to squeeze the last drop of processing power out of it.

    You are correct in that Intel appears to have copied the ring network of the Cell BE, although I don't understand why they need it in addition to the coherent cache. Oh, well, guess I'll have to wait until the paper really hits the public.

  • Re:OpenGL (Score:4, Informative)

    by TheRaven64 (641858) on Monday August 04, 2008 @11:26AM (#24467369) Journal

    OpenGL is just an abstraction layer. Mesa implements OpenGL entirely in software. Implementing it 'in hardware' doesn't really mean 'in hardware' either, it means implementing it in software for a coprocessor that has an instruction set better suited to graphical operations than the host machine.

    Sure, you could write your own rasteriser for Larrabee, but it wouldn't make sense to do so. If you use an off-the-shelf one then a lot more people are likely to be working on optimising it. And if you're implementing an off-the-shelf rasteriser, then implementing an open specification like OpenGL for the API makes more sense than making everyone learn a new one, and means that there's already a load of code out there that can make use of it.

  • by Vaystrem (761) on Monday August 04, 2008 @11:36AM (#24467511)

    That is much more detailed than the one linked in the article summary. It can be found here. [anandtech.com]

  • by robthebloke (1308483) on Monday August 04, 2008 @01:53PM (#24469863)
    One language that is being used in the sceintific community right now is CUDA - which runs on a GPU and is C based.

    In addition, Fortran to C tools have been around for some years. To say that Fortran is the only scientific language is BS. R [r-project.org], S Plus [insightful.com], Octave [wikipedia.org], matlab [mathworks.com], perl and CUDA [nvidia.com] to name a few. Taking R as an example - it provides an code interface that allows you to write optimised C/C++ routines and utilise those in the language itself.
  • by Anonymous Coward on Monday August 04, 2008 @02:37PM (#24470533)

    Nobody is arguing that Intel makes good graphics hardware. They make adequate graphics hardware that the majority use without problems.

    Go to any non-gaming office building and tell me how many Intel graphics vs Nvidia and ATI you find. I am willing to bet that most, if not all, of them will be Intel.

  • Re:Good old SIGGRAPH (Score:3, Informative)

    by TheRaven64 (641858) on Monday August 04, 2008 @03:05PM (#24470891) Journal
    Not really. A lot of good papers go to IEEE Visualisation and a few other conferences. Outside the US, Eurographics is pretty well respected too. SIGGRAPH is the largest conference, and probably the highest impact factor, but it's certainly not the only one people care about.
  • Re:Good news (Score:3, Informative)

    by Creepy (93888) on Monday August 04, 2008 @03:07PM (#24470915) Journal

    They've stated that it will be a 150W+ chip on a PCI Express 2 card, as I recall, and is intended as a GPU, though it will be fully programmable and have CPU capability (so when not doing GPU stuff, it could serve as extra CPUs). It is intended to compete in the high end graphics market.

    Essentially, it's a clutch of high performance software vector units in parallel with a bunch of CPUs. Graphics scale with each added processor because it is a software driven architecture, whereas traditional GPUs don't scale because they have a fixed function pipeline (if everything were written for shaders, I would think it would scale). One of the things Intel is touting is Binned rendering (aka chunked or tile rendering), which is breaking the frame into tiles and storing a list of front-to-back polygons in off-chip memory and the tile buffer is scaled to cache. Technically, this should be no faster than z-buffering, but I believe they're sorting and ray casting and in a brute-force sort of way this is faster than z-buffering. What I don't get here is how they get "2-7x the performance" because they have the extra sort step.

    By the way, if you look at CPUs, Intel's Core2 line has five power designations:
    X - Extreme - power > 75W
    E - Standard Desktop 55-75W
    T - Standard Mobile 25-55W
    L - Low Voltage 15-25W (their name - they mean low power)
    U - Ultra Low Voltage - Power < 15W

    According to Wikipedia [wikipedia.org] the mini uses mobile processors (the T designation). Max power consumption of most laptops is 80W, so it is likely your mini maxes at 80W.

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