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Subject: Re: Crafty SMP questions.

Author: Slater Wold

Date: 21:09:32 08/05/03

Go up one level in this thread


On August 05, 2003 at 23:54:42, Slater Wold wrote:

>On August 05, 2003 at 20:00:44, Robert Hyatt wrote:
>
>>On August 05, 2003 at 19:13:21, Slater Wold wrote:
>>
>>>On August 05, 2003 at 18:38:51, Robert Hyatt wrote:
>>>
>>>>On August 05, 2003 at 17:30:51, Matthew Hull wrote:
>>>>
>>>>>Does Crafty scale above 4 processors?  For example, could crafty utilize all the
>>>>>CPUs on an IBM pSeries 690 7040-681T 32-way?
>>>>>
>>>>>http://www-132.ibm.com/content/home/store_IBMPublicUSA/en_US/eServer/pSeries/high_end/690.html
>>>>>
>>>>>MH
>>>>
>>>>
>>>>I didn't have time to look closely.  But it is most likely a NUMA platform,
>>>>which means that Crafty as it exists now is not going to work well on it.  NUMA
>>>>machines require careful attention to what is put where in memory, so that
>>>>often-used data is as close to the physical processor (in terms of access
>>>>latency) as possible.  The current implementation of SMP in Crafty is based
>>>>on pure SMP, where memory is simply shared.
>>>>
>>>>If I ever have time to fiddle with a NUMA machine, I'll probably look at
>>>>fixing the major issue, which is to put split blocks close to each processor,
>>>>and when giving a specific processor a tree to search, using a split block that
>>>>is _close_ to it.
>>>
>>>I really don't think it is a NUMA machine.
>>>
>>>"Advanced symmetric multiprocessing (SMP) up to 32-way", is how the exactly
>>>describe it.
>>>
>>>And when you go to their 'Clusters' section, this machine isn't mentioned.
>>
>>
>>NUMA is not necessarily a "cluster".  There are several machines that are
>>called "SMP" but also use a NUMA approach for memory.  The clue is the price.
>>A real 32-way shared memory system is _really_ expensive.  Cray claimed that
>>50+% of the price of the T932 was in the memory interconnect to support full
>>memory speed to all processors.
>>
>>Of course, I'm not wagering anything on this "hip shot" as to the idea behind
>>the machine, but from what I have seen in past years, anything beyond 8 CPUS
>>is either _way_ expensive, or NUMA.
>
>Sorry, I mispoke myself....scratch that, let's try again.
>
>Reading
>http://www-1.ibm.com/servers/eserver/pseries/hardware/whitepapers/p690_config.pdf,
>it would appear that it is a true SMP system.
>
>IBM has their own way of doing things, using MCMs and such, with the GX
>controllers.
>
>
>32 64-bit 1.7Ghz POWER4+ CPUs, 512GB RAM, and Crafty 19.04.  Whew.

Oh, and..."Pricing for the p690 starts at US$493,386 with an eight-way
configuration featuring Power4+ 1.5 GHz processors, 8 GB of main memory and two
36 GB disk drives with AIX preinstalled."

Starts...at...half...a...million...dollars...

That's about $62k per CPU+1GB RAM.  Take off 10% for each CPU+1GB RAM.

Add 24 CPUs, then add 24GB RAM.  You're at somewhere around $2M.



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