Author: Jeremiah Penery
Date: 22:19:00 07/08/03
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On July 09, 2003 at 00:09:03, Vincent Diepeveen wrote: >On July 08, 2003 at 19:37:48, Jeremiah Penery wrote: > >>On July 08, 2003 at 08:37:49, Vincent Diepeveen wrote: >> >>>On July 08, 2003 at 00:33:09, Jeremiah Penery wrote: >>> >>>>Each chip consumes only about 140W, rather than Vincent's assertion of 150KW. >>> >>>the 125KW is for Cray 'processors' not fujitsu processors that are in the NEC >>>machine. >>> >>>Ask bob i remember he quoted 500 kilowatt for a 4 processor Cray. So i divided >>>that by 4. >> >>That 500KW was probably for the entire machine. Each processor probably > >Yes a 4 processor Cray. > >Just for your own understanding of what a cray is. it is NOT a processor. >It is a big block of electronics put together. So no wonder it eats quite a bit >more than the average cpu. Your own words: "the 125KW is for Cray 'processors'". But that is not the truth. >Another major difference with Cray machines (using cray processor blocks) is >typically not using too many processors, because all processors are cross >connected with very fast connections. No clever routing system at all. Brute >force. Earth Simulator: Each node of 8 processors is connected to 128 IN (Interconnected Network) cabinets. Each of those cabinets is connected to each other processing nodes (all 639 other nodes). Each of these connections is 12.3GB/s bi-directional. Each IN cabinet has 2 640x640 crossbar switches to handle this. "Several data-transfer modes, including access to three-dimensional (3D) sub-arrays and indirect access modes, are realized in hardware. In an operation that involves access to the data of a sub-array, the data is moved from one PN [processor node] to another in a single hardware operation..." So, basically, every processor has 1-hop access to every other processor's memory. I guess that's how the machine sustained over 85% of theoretical peak performace on LINPACK, and 66% of theoretical peak on a real-world atmospheric simulation.
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