The one and only Folding @ Home thread

Discussion in 'Graphics and Semiconductor Industry' started by ShaidarHaran, Apr 7, 2010.

  1. ShaidarHaran

    ShaidarHaran hardware monkey
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    This isn't true. The F@H GPU2 client distributes the same work units to NV and ATi hardware. The client works differently on Radeons and Geforces, but it is processing the same dataset.

    That sounds like what I alluded to hearing previously.

    For the record, I'm not here to evangelize NV hardware, I'd rather have a good option from both IHVs (or more, if Intel ever joins the playing field).

    I think it's a relevant observation to make though, given the state of the market. We've all heard the stories about NV devrel working closely with devs to make sure their software runs properly on Geforces but we rarely hear about ATi doing the same.
     
  2. willardjuice

    willardjuice super willyjuice
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    It is a fair characterization. The AMD f@h client was capped to use at most ~320 shader processors, hence why the only performance increases come from clock increases.
     
  3. rpg.314

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    In computational molecular dynamics, it is. The reasons for AMD's trailing F@H perf are something else, tool and code base maturity being one of them.
     
  4. Arnold Beckenbauer

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    Is F@H somekind of Holly Grail of GPGPU?
    Look at this:
    Milkyway@home
    Collatz@home
    distributed.net
    Is it so?
    http://foldingforum.org/viewtopic.php?f=51&t=10442#p103025
     
  5. larrabee

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    i remember some things from the fah whitepapers. you have to pay to view it now. the nvidia client was a port of the ATi client. the ATi client used an earlier version of brook and older hardware. random numbers had to be generated on cpu due to no integer support in brook and i think their was some restriction with gathers/scatters from kernels that nvidia didnt have. nvidia helped add some optimizations like use of LDS which gives them a nice performance boost. its more accurate too because ATi reuses random numbers to save time. they want to use opencl to have one codebase so they can use all hardware to do the same projects. hopefully ATi can get a boost with evergreen's LDS. fermi's caches could help a lot though.
     
  6. ShaidarHaran

    ShaidarHaran hardware monkey
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    Right, but this decision by Pande Group/ATi seems rather short-sighted now. Due to ATi's lack of continued involvement in F@H, application performance doesn't scale with new hardware. NV doesn't have this problem, F@H scales nicely across generations of hardware.

    I'm suggesting that NV has better software support and flexibility. To this day my roommate gets to "enjoy" Borderlands sans Vsync and AA, whereas I run Vsync and 16xQ CSAA on my GTX 285, with nary an FPS hiccup to boot.

    That's part of my argument. NV has a superior toolset and it shows.

    It's not a holy grail by any means, but it is the most popular GPGPU application, and by far the most popular distributed computing app. The hundreds of thousands of active F@H users outweighs every other DC community, to my knowledge.

    The performance just isn't there. ATi GPUs are easily outdistanced by NV GPUs in F@H, regardless of the work unit in question. For example, my roommate's 4870x2 has produced 3000-4000 points per day (PPD) at most, while my GT200b farm produces 8000-10000 PPD, per GPU, on average.
     
  7. CarstenS

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    Obviously, I see your point. But please try and see the customer's point of view also: From that purely customers point of view, I won't care who's to take the blame. All I'd care for in this case is that I have an application that I'd like to run and not only run, but run fast, really fast.

    And I know from all the reviews over the web that the chip's got the raw power to really own that application - as we see in things Gipsel regularly mentions like Milkyway@Home or Collatz@Home. But 'my' app just won't run fast. That's disappointing for me, so i quit folding for the time being.
     
  8. Mintmaster

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    Buddy, if the algorithm is different, then the workload is different. If I have one program doing bubble sort and another doing quicksort, and both are fed the same random sequence of numbers to sort, then the hardware sees a different workload from each.

    That's because none of the features of Cypress are being used. Heck, none of the features of even RV770 are even being used, including basic scatter, according to their paper. The GPU2 client was developed for R600 hardware.
    For some reason, it only uses a hardcoded number of stream processors on ATI. I think a change was eventually made to make the client use 800 SPs instead of 320 so that RV770 was notably faster than R600, but AFAIK the client is still only using half the SPs on Cypress.
     
  9. willardjuice

    willardjuice super willyjuice
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    Fixed. Which brings us back to the original point, don't blame AMD's hardware (or in this case I would even argue software) for Pande's shortcomings.

    But I don't think this is true. How does AMD's "lack of continued involvement" have anything to do with Pande not removing the cap for the F@H client? It's their code (not AMD's code)! Regardless if AMD is helping or not, there's no excuse for Pande to not update and maintain their code. The notion that the only way developers can improve their code base is with an IHV's help is ridiculous (and that goes for anything, not just F@H).
     
  10. ShaidarHaran

    ShaidarHaran hardware monkey
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    They're getting the same work units and outputting the same results. The only difference I'm aware of is the fact that ATi needs to redo some calculations.

    Yes, that is my understanding of the current situation WRT the GPU client V2. So we're back at the beginning again. NV hardware is faster than ATi hardware for F@H.
     
  11. ShaidarHaran

    ShaidarHaran hardware monkey
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    Why not? NV has no such limitations.

    NV worked closely w/Pande Group to update the GPU V2 client to run well on Geforces. ATi did not. At least until the next version of the client based upon OpenCL is released, existing versions haven't had a vendor-agnostic API to work through, and so have run much closer to the metal, requiring interaction from the IHV to achieve decent stability and performance.
     
  12. aaronspink

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    Honestly? The less resources ATI wastes on F@H the better. They are better off working on infrastructure and tools aimed at a larger community. The reality is that the F@H group should port their codebase to opencl and then it will just work with whatever.
     
  13. Dave Baumann

    Dave Baumann Gamerscore Wh...
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    Indeed, and we're all behind their movement to OpenCL.
     
  14. ShaidarHaran

    ShaidarHaran hardware monkey
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    Using what graphics card? My roommate is running his copy through Steam. Running Vista 64.

    I don't know what ATi's involvement has been in the specific games you mentioned, but I understand it is greater than many titles in the past. It's nice to see this, but pardon me if I'm a bit hesitant to believe ATi's devrel will be on-par with NV's any time soon, especially WRT F@H.
     
  15. Dave Baumann

    Dave Baumann Gamerscore Wh...
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    Incorrect. Mike would be exceedingly upset to see that. Lots of effort was put into the GPU2 client for Brook+.
     
  16. ShaidarHaran

    ShaidarHaran hardware monkey
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    I agree. I don't like the current performance level ATi GPUs provide for F@H, but I think this is the best solution in the long run.
     
  17. ShaidarHaran

    ShaidarHaran hardware monkey
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    You're right, I shouldn't be stating ATi hasn't done any work WRT F@H, it just appears that way to me based on the performance with successive hardware generations. Do you know why the client appears to have a cap on how many SIMDs it runs upon on ATi hardware?
     
  18. aaronspink

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    Unlikely. As much as it pains me to say it, I would suggest that video transcoding likely is used more than F@H and even that isn't used that much.


    Might have something to do with when the clients were written.
     
  19. aaronspink

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    So?


    Maybe you should stop worrying about epeening with PPD and just actually do something useful with your computer.
     
  20. ShaidarHaran

    ShaidarHaran hardware monkey
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    That would be the logical alternative, but I'm not sure how you could prove it. Active users of transcoding software aren't tracked like F@H.

    I imagine the GPU v2 client was written and optimized for both IHVs hardware at approximately the same time. The installation executable for the GPU V2 client supports both ATi & NV hardware.
     
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