[Beowulf] ARM cpu's and development boards and research

Prentice Bisbal prentice.bisbal at rutgers.edu
Wed Nov 28 13:47:49 PST 2012


On 11/28/2012 11:27 AM, Vincent Diepeveen wrote:
>
> On Nov 28, 2012, at 4:30 PM, Prentice Bisbal wrote:
>
>>
>> On 11/27/2012 07:32 PM, Vincent Diepeveen wrote:
>>>
>>> On Nov 28, 2012, at 12:17 AM, Prentice Bisbal wrote:
>>>
>>>>
>>>> On 11/27/2012 03:37 PM, Douglas Eadline wrote:
>>>>>
>>>>>> My interest in Arm has been the flip side of balancing flops to 
>>>>>> network
>>>>>> bandwidth.  A standard dual socket (AMD or Intel) can trivially 
>>>>>> saturate
>>>>>> GigE.  One option for improving the flops/network balance is to add
>>>>>> network bandwidth with Infiniband.  Another is a slower, cheaper, 
>>>>>> cooler
>>>>>> CPU and GigE.
>>>>>>
>>>>> applause.
>>>>
>>>> I applaud that applause.
>>>>
>>>> What Bill has just described is known as an "Amdahl-balanced system",
>>>> and is the design philosophy between the IBM Blue Genes and also
>>>> SiCortex. In my opinion, this is the future of HPC. Use lower power,
>>>> slower processors, and then try to improve network performance to 
>>>> reduce
>>>> the cost of scaling out. Essentially, you want the processors to be
>>>> *just* fast enough to keep ahead of the networking and memory, but no
>>>> faster to optimize energy savings.
>>>
>>> For HPC the winning concept seems to be increasing corecount at 
>>> manycores.
>>>
>>> We also see how bluegene couldn't keep its concept - it's having 
>>> what is it 18+ cores
>>> now or so?
>>
>> It's not 18+. It's exactly 18 cores. And only 16 are used for 
>> computation. One is used for operating system overhead, and the other 
>> is a spare.
>> This is exactly in keeping with the Blue Gene Concept, which is using 
>> low-power processors to conserve energy connected to highly-optimized 
>> interconnects to create a more balanced system.  'Low-power' and 'low 
>> core-count' are not the same thing.
>>
>
>
> Here is what wiki says on the original concept: "Trading the speed of 
> processors for lower power consumption. Blue Gene/L used low frequency 
> and low power embedded PowerPC cores with floating point 
> accelerators.While the performance of each chip was relatively low, 
> the system could achieve better performance to energy ratio, for 
> applications that could use larger numbers of nodes."
>
> It's obvious this won't be the case in the future.
>
> It means the future is big fat manycores eating a ton of power for 
> each CPU.
>
> Arguing then that each core is low power is not relevant - it's not 
> the original concept of the CPU being low power and embedded
> as you can see from the wikisayings.

*Sigh*... Many lower-powered cores can still equal a low-powered 
complete processors.




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