mersenneforum.org The prime-crunching on dedicated hardware FAQ (II)
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 2011-09-17, 06:57 #23 Dubslow Basketry That Evening!     "Bunslow the Bold" Jun 2011 40
2011-09-17, 18:55   #24
Christenson

Dec 2010
Monticello

5×359 Posts

Quote:
 Originally Posted by Dubslow http://www.supermicro.com/GPU/
Interesting stuff... but I suspect that's out of "average" consumer range, and therefore Jason's original argument applies.

GPUs now do LLs and TFs, and do TF exteremely efficiently compared to CPUs, and they suddenly aren't "Dedicated Hardware" anymore. See mfaktc, mfakto, and CUDALucas. They also aren't yet integrated into P95.

When we think of "Dedicated Hardware" at this point, we need something more than a collection of GPUs, like maybe an FPGA pipeline.

2011-09-18, 16:14   #25
jasonp
Tribal Bullet

Oct 2004

3×7×132 Posts

Quote:
 Originally Posted by Dubslow Man... Just spent the last hour wikipedia'ing about super computers... Even 150th place would double the entire GIMPS throughput... (http://www.top500.org/list/2011/06/200)
Yes, this is the reason I hopped off the ever-faster-main-home-system treadmill around 2007. Greg and Ilya have run NFS linear algebra on parallel systems using 256 up to over 900 MPI processes, in one case reducing computations that would have taken a year down to 2.5 days. Nothing you can do to a home system would let you duplicate that kind of performance. On the one hand, Teragrid is a rationed resource, but on the other hand if you can find someone in government or academia to write a mini-proposal on your behalf then they'll give you 50000 CPU hours essentially no questions asked.

 2011-09-18, 19:52 #26 Christenson     Dec 2010 Monticello 34038 Posts The question in my mind is, supposing I want to do better (more GHz-days per day, or fewer joules/GHz day) than my reasonably fast multi-core home system with a GTX560 GPU, what's the minimum hardware investment and amount of power supply that would be needed? Aren't supercomputers on a treadmill too? These "server" systems just don't seem to be an economic way to go, but maybe I'm looking in the wrong corner of the market. Incidentally, user BDodson is in academia (I was acquainted with him personally about 15 years ago)...and GIMPS is gathering 50,000 CPU hours on a daily basis from random users such as myself.
 2011-09-19, 13:35 #27 jasonp Tribal Bullet     Oct 2004 354910 Posts Right now you and I have different objective functions to optimize, and you have more choices because the work you want done can proceed perfectly in parallel.
2011-09-20, 01:23   #28
Christenson

Dec 2010
Monticello

111000000112 Posts

Quote:
 Originally Posted by jasonp Right now you and I have different objective functions to optimize, and you have more choices because the work you want done can proceed perfectly in parallel.
I was thinking more in terms of your objective functions than my (somewhat naive) ones. I imagine you wanting to finish that last, linear algebra step on various GNFS jobs...requiring both massive computation and massive communications....I have not forgotten.

The question was, if I wanted to make a dent in those big problems, how much $$would I need to spend on what kind of hardware, and how much electricity would I use running it? The big clusters (Lomonosov, teragrid) are now a few years old, so should cost a bit less to begin to duplicate....  2011-09-20, 09:20 #29 fivemack (loop (#_fork)) Feb 2006 Cambridge, England 193616 Posts The problem is that the big clusters are actually-big; Lomonsov is twenty racks full of 2010-era servers, and the procurement process began with the relatively-rich Russian state wanting to have a big computer for its most prestigious university. The big supercomputer facilities are quite close to 'spec up a reasonably powerful server and buy {one, ten} thousand', and so cost one to ten thousand times more than a basement server. They're fundamentally not susceptible of imitation, in the same sort of way that space programs aren't. You could start sticking quad-Opteron 6168 boxes together with QDR Infiniband in your basement, but at the price of a second-hand decent car for each box and for the Infiniband switch, that's quite a good way to spend a very large amount of your money on a resource which will be almost surely under-used.  2011-09-20, 12:47 #30 Christenson Dec 2010 Monticello 5·359 Posts Got to start with that "large amount of$$" part...I haven't got it....I was thinking that if I had the computer, jasonp would have little trouble putting it to 100% work, if I was willing to pay for the electricity. I was wondering how well funded GIMPS would need to be to afford even a shadow of one of those clusters.....it took no time for the forum to come up with $500 when it was needed.  2011-09-20, 12:50 #31 jasonp Tribal Bullet Oct 2004 3×7×132 Posts GIMPS is already a 501(c)(3) charity, and the last mersenneforum drive collected more in donations than GIMPS has ever made. I don't know if that can be changed. You occasionally find older Cray machines for auction on eBay, but the specs on an older Cray machine are laughable compared to a hot modern server, plus the big ones cost a million dollars a year just to keep turned on and healthy. TACC recently upgraded the Lonestar cluster to very powerful 12-core nodes, and Teragrid has added many existing clusters from universities in just the last 6 months or so. Last fiddled with by jasonp on 2011-09-20 at 12:55 2011-09-20, 13:03 #32 Xyzzy Aug 2002 7×1,217 Posts Quote:  …it took no time for the forum to come up with$500 when it was needed.

2011-09-20, 13:31   #33
jasonp
Tribal Bullet

Oct 2004

3×7×132 Posts

Quote:
What a great thread. Is that Salem guy still protesting by turning off more computers?

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