【正文】 1 million times faster ? Combine thousands of processors ? Parallel puter ?Multiple processors ?Supports parallel programming ? Parallel puting = Using a parallel puter to execute a program faster Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Why Didn’t Everybody Buy One? ? Superputer ? ? CPUs ?Computation rate ? throughput ?Inadequate I/O ? Software ?Inadequate operating systems ?Inadequate programming environments Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Advanced Strategic Computing Initiative ? . nuclear policy changes ?Moratorium on testing ?Production of new weapons halted ? Numerical simulations needed to maintain existing stockpile ? Five superputers costing up to $100 million each Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Data Parallelism ? Independent tasks apply same operation to different elements of a data set ? Okay to perform operations concurrently for i ? 0 to 99 do a[i] ? b[i] + c[i] endfor Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Data Clustering ? Data mining = looking for meaningful patterns in large data sets ? Data clustering = anizing a data set into clusters of “similar” items ? Data clustering can speed retrieval of related items Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Data Parallelism Opportunities ? Operation being applied to a data set ? Examples ?Generating document vectors ?Finding closest center to each vector ?Picking initial values of cluster centers Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Strategy 1: Extend Compilers ? Parallelizing piler ?Detect parallelism in sequential program ?Produce parallel executable program ? Focus on making Fortran programs parallel Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Extend Language (cont.) ? Advantages ?Easiest, quickest, and least expensive ?Allows existing piler technology to be leveraged ?New libraries can be ready soon after new parallel puters are available Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. New Parallel Languages (cont.) ? Advantages ? Allows programmer to municate parallelism to piler ? Improves probability that executable will achieve high performance ? Disadvantages ? Requires development of new pilers ? New languages may not bee standards ? Programmer resistance Copyright