[Beowulf] The Walmart Compute Node?

[Douglas Eadline]

> Doug,
> Thanks. I visited Clustermonkey before I came here. There's just too
> much good stuff.
> There was discussion previously, I think, maybe elsewhere, about the
> NIC card offloading some work from the CPU, as opposed to on-board
> ethernet...which is what you mean in the case of getting nics for the
> PCIe slot "vs 32 PCI"...oh you mean PCIe card as opposed to PCI card,
> not as opposed to the onboard connection. These walmart things have
> one connection on board, is that worth replacing with a card?

Many of the new low cost motherboards use PCIe to connect onboard
NICS. These should be able perform well but often don't due to
driver issues or cheap chipsets. Some still use 32bit PCI
interface as well. It all depends on the chipset.

Most modern low-cost boards also have at least a 1X PCIe
slot into which and Intel PT desktop NIC ($40) can be used.
While these are not IB or Myrinet, they do perform well
for a low cost part. TCP latency measured by Netpipe
is usually less than 30 µs (through a switch, 10.8 µs has been
reported if you use GAMMA). Look at the Netpipe data
below to see how these NICs compare to 32 bit PCI NICs.

http://basement-supercomputing.com/download/benchmarks/Intel-PT-PCIe/netpipe.Intel-PT-PCIe-throughput_vs_blocksize.png


--
Doug

> Thanks,
> Peter
>
> On Nov 8, 2007 3:36 PM, Douglas Eadline <deadline at eadline.org> wrote:
>> Peter,
>>
>> Having some experience with low cost hardware, If you are
>> doing number crunching multi-core seems to provide the
>> best bang for buck. The following is the HPL performance that
>> you can get for $2500. The Kronos and Microwulf clusters
>> are detailed on http://clustermonkey.net, Norbert is the subject
>> of a November Linux Magazine article.
>>
>>                                         CPU
>> Cluster Name                  Clock      Release           HPL
>>   Processor               Speed (MHz)   Date         Performance
>> ---------------------------------------------------------------------
>> Kronos/Sempron 2500+ (8)        1750   7/2004    14.90 GFLOPS (Atlas)
>> Microwulf/Athlon64 X2 3800+ (4) 2000   8/2005    26.25 GFLOPS (Goto)
>> Norbert/Core Duo E6550 (4)      2333   7/2007    45.55 GFLOPS (Goto)
>>
>>
>> If you draw a line (3 points I know) you get to 80 GFLOPS
>> by 2010. Actually with some tweaking I got Norbert
>> up to 47.7 HPL GFLOPS. And, notice I qaulify the performance
>> as "HPL GFLOPS" as YMMV.
>>
>> With really low cost systems one important aspect is the
>> interconnect. The PCIe buses on low end motherboards allows
>> one to use inexpensive PCIe (Intel) Ethernet cards vs
>> 32 PCI. Some of the on-board GigE implementations are
>> not very good.
>>
>> --
>> Doug
>>
>>
>>
>>
>>
>> > Recently, probably you noticed, Walmart began selling a $200 linux PC.
>> > (Apparently the OS is just Ubuntu 7.10 with a small xindow manager
>> > instead of Gnome or KDE). Now Slashdot points to
>> > http://www.linuxdevices.com/news/NS5305482907.html, the MB being sold
>> > separately for $60 ("development board"). It has 1.5GHz CPU,
>> > unpopulated memory (slots for 2GB), one 10/100 connection. Does this
>> > look to y'all like fair FLOPS/$ for a kitchen project? I'm thinking 6
>> > of them as compute nodes per 8 port router, with a bigger head node
>> > for fileserving. (actually I'll use a spare room but you know what I
>> > mean). An arrangement like this might be faster RAM access per core,
>> > compared to multicore, since each core has no competition for is't own
>> > memory, right?
>> > Thanks,
>> > Peter
>> > _______________________________________________
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>> >
>> >
>> >
>>
>>
>> --
>> Doug
>>
>
> !DSPAM:473379d814678362916074!
>


-- 
Doug