[Beowulf] Benchmark between Dell Poweredge 1950 And 1435

Robert G. Brown rgb at phy.duke.edu
Mon Mar 12 13:40:27 EDT 2007

On Mon, 12 Mar 2007, Bill Broadley wrote:

> Robert G. Brown wrote:
>> It's worth a small editorial insertion here that I "like" hypertransport
>> for a variety of reasons -- perhaps because it is a packet-based
>> internal network that makes your computer's CPU-memory architecture
>> surprising like a cluster in miniature on the inside.  And just like any
>> compute cluster, you need to tune your design choices towards your
>> application.
> I agree completely.  Sad that AMD doesn't play to their strength. 
> Hypertransport had the potential for significant differentiation from
> Intel solutions.  Currently it allows for dual sockets with somewhat
> better memory performance that Intel's latest greatest dual FSB
> woodcrest machines.  The story on quad socket shows a clear and
> substantial advantage for hypertransport, but alas most of the market
> isn't in quad sockets.
> Seems like if AMD didn't get so stingy with the coherent HT links (which
> only the 8xx chips usually have spare ports) that the market might generate
> some really interesting opteron based solutions.

Have you looked over the HT consortium site?  It is truly a lovely spec
but they didn't quite make the most of their brief window of opportunity
to kill off the bus.  Everybody went PCI-X instead of HT.  I don't know
if this was due to Intel FUD, or a lack of energy from other consortium
members, or the difficulty of overcoming vendor persistence in sticking
with PCI or... most likely it was just the lack of Intel support.
Who would invest in an HT connection for their network card when it will
never run on 3/4 of all servers made by design?  I've seen this before,
a couple of times, over the lifetime of the PC.  Somebody comes up with
a couple of competing bus designs, sometimes there are even cards
released for both, but eventually Intel gets behind just one or the
other proves unscalable, and... the rest is history, at least for 4-5
years until the next one comes along.

Intel isn't anywhere nearly as bad as Microsoft, and there have "always"
been 2-3 makers of competing Intel compatible chips, since shortly after
the PC.  AMD is just the survivor of this last-man-standing competition
and they do have the chops to do some really good things.  The opteron
really gave them a solid chunk of the high performance market and a lot
of cred.  But definitely -- they needed to carry HT a lot further,
because it was very much one of the major advantages of their entire
design philosophy that has never quite made it big.


> After all if pathscale can manage hypertransport -> IB, how much harder
> would shared memory be..... if of course coherent HT worked at a reasonable
> price.
> Or maybe if Nvidia can manage to build a low volume video card
> with 768MB and a 80GB/sec memory system for $560 maybe some enterprising 
> company could build a opteron based motherboard with amazing memory
> bandwidth..... if of course coherent HT worked at a reasonable
> price.
> Why shouldn't a video card be able to directly access all memory (and
> vice versa)?
> Then again maybe this is what AMD's torenza initiative is about
> Seems like AMD stands to gain much more from the potential of
> future coherent HT products then they do by losing $$$'s on lower
> prices for the 8xx and 8xxx products vs the 2xx and 2xxxx products.
> Not to mention if the world bought more quad socket machines that would
> be a world that AMD would have a much larger lead in (because of
> the onchip memory controller).

Robert G. Brown	                       http://www.phy.duke.edu/~rgb/
Duke University Dept. of Physics, Box 90305
Durham, N.C. 27708-0305
Phone: 1-919-660-2567  Fax: 919-660-2525     email:rgb at phy.duke.edu

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