【正文】 hapter 1 Motivation and History Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. 50 Years of Speed Increases ENIAC 350 flops Today 1 trillion flops Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Pipelining ? Divide a process into stages ? Produce several items simultaneously Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Add a Parallel Programming Layer ? Lower layer ? Core of putation ? Process manipulates its portion of data to produce its portion of result ? Upper layer ? Creation and synchronization of processes ? Partitioning of data among processes ? A few research prototypes have been built based on these principles Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Extend Compilers (cont.) ? Disadvantages ?Parallelism may be irretrivably lost when programs written in sequential languages ?Performance of parallelizing pilers on broad range of applications still up in air Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Seeking Concurrency ? Data dependence graphs ? Data parallelism ? Functional parallelism ? Pipelining Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Modern Scientific Method Nature Observation Theory Physical Experimentation Numerical Simulation Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Why MPI? ? MPI = “Message Passing Interface” ? Standard specification for messagepassing libraries ? Libraries available on virtually all parallel puters ? Free libraries also available for works of workstations or modity clusters Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Beowulf Concept ? NASA (Sterling and Becker) ? Commodity processors ? Commodity interconnect ? Linux operating system ? Message Passing Interface (MPI) library ? High performance/$ for certain applications Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Programming Parallel Computers ? Extend pilers: translate sequential programs into parallel programs ? Extend languages: add parallel operations ? Add parallel language layer on top of sequential language ? Define totally new parallel language and piler system Copyright 169。 The McGrawHill Companies, Inc. Permission required for reproduction or display. Current Status ? Lowlevel approach is most popular ? Augment existing language w