Author: Robert Hyatt
Date: 21:21:09 08/05/03
Go up one level in this thread
On August 06, 2003 at 00:09:32, Slater Wold wrote: >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. at that price it _could_ be a real SMP platform... And Crafty _should_ scale just fine on it...
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