Basic HTML version of Foils prepared 10 Sept 1996

Foil 27 Vector Supercomputers in a Nutshell - II

From New CPS615Master Foils-- 26 August 96 Basic Simulation Track for Computational Science CPS615 -- Fall Semester 96. by Geoffrey C. Fox


1 Vector machines pipeline data through the CPU
2 They are not so popular/relevant as in the past as
  • Improved C.P.U. architecture needs fewer cycles than before for each (complex) operation (e.g 4 now not ~100 as in past)
  • 8 Mhz 8087 of Cosmic Cube took 160 to 400 clock cycles to do a full floating point operation in 1983
  • Applications need more flexible pipelines which allow different operations to be executed on consequitive operands as they stream through CPU
  • Modern RISC processors (super scalar) can support such complex pipelines as they have far more logic than CPU's of the past
3 In fact excellence of say, Cray C-90 is due to its very good memory architecture allowing one to get enough operands to sustain pipeline.
4 Most workstation class machines have "good" CPU's but can never get enough data from memory to sustain good performance except for a few cache intensive applications

in Table To:


© on Tue Oct 7 1997