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NEC SX-9 to be World's Fastest Vector Computer
An anonymous reader writes "NEC has announced the NEC SX-9 claiming it to be the fastest vector computer, with single core speeds of up to 102.4 GFLOPS and up to 1.6TFLOPS on a single node incorporating multiple CPUs. The machines can be used in complex large-scale computation, such as climates, aeronautics and space, environmental simulations, fluid dynamics, through the processing of array-handling with a single vector instruction. Yes, it runs a UNIX System V-compatible OS."
Well, distributed is often seen as poor-mans parallel, but in this case they don't compare. Vector units have large arrays of data and perform the same operation on all of them at once. Think array or matrix operations being done in one step rather than needing loops. This is where a SIMD architecture takes off.
The only unit I ever got to play with had a 64x32 grid of processors, you could add a row of numbers in log2(n) steps instead on n. It was cool because you could tell each processor to grab a value from the guy next to him (or n steps in a given direction from him) and so on. You could calculate dot products of matrices very quickly.
The distributed stuff you mentioned is mostly farming. Take a big loop of independent steps, break them up and pass them out to a (possibly) heterogeneous collection of processing nodes. Collect the answers when they finish. Render farms work the same way. It's a good way to break up some problems, but it's not what a vector unit does.
Now, I haven't touched this stuff for eleven years so my facts are possibly wrong. I'm sure someone will be along to correct me.
The cost of the supercomputers is so high, that sometimes several man-month of tailoring the software to run as efficient as possible on the hardware could be recovered during a couple of days of processing.
For the kind of computation the supercomputer market requests, a 5% improvement in running speed on a supercomputer can worth millions
http://www.nec.de/hpc/hardware/sx-series/index.html
There are four PDFs there; the brochure is a four-colour glossy, but there is some real information. Sadly, the interesting-looking white papers are for the SX6, two generations earlier.
SX9 summary: 65nm technology, 3.2GHz clock speed, eight vector elements handled per cycle with two multiply and two add units, which is where the 102.4Gflop/CPU figure comes from. 16 CPUs in a box about the size of a standard 42U rack.
Totally absurdly fast (ten 64-bit words per cycle per CPU) access to a large (options are 512GB or 1TB) shared main memory; absurdly fast (128GB/second) inter-node bandwidth.
That's the current, popular, Blue Gene/L architecture. The Blue Genes are composed of densely packed boards, each of which has a PowerPC chip and many vector processors. The PowerPC chips run a Linux-like OS and do some normal-looking I/O (filesystems, networking, etc), while the vector processors churn lots of data and have simplistic I/O.
That GP who suggests that Xen is used to distribute tasks obviously isn't familiar with the needs of big iron.