Motivation and History参考.pptVIP

Parallel Programmingin C with MPI and OpenMP Michael J. Quinn Chapter 1 Motivation and History Outline Motivation Modern scientific method Evolution of supercomputing Modern parallel computers Seeking concurrency Data clustering case study Programming parallel computers Why Faster Computers? Solve compute-intensive problems faster Make infeasible problems feasible Reduce design time Solve larger problems in same amount of time Improve answer’s precision Reduce design time Gain competitive advantage Definitions Parallel computing Using parallel computer to solve single problems faster Parallel computer Multiple-processor system supporting parallel programming Parallel programming Programming in a language that supports concurrency explicitly Why MPI? MPI = “Message Passing Interface” Standard specification for message-passing libraries Libraries available on virtually all parallel computers Free libraries also available for networks of workstations or commodity clusters Why OpenMP? OpenMP an application programming interface (API) for shared-memory systems Supports higher performance parallel programming of symmetrical multiprocessors Classical Science Modern Scientific Method Evolution of Supercomputing World War II Hand-computed artillery tables Need to speed computations ENIAC Cold War Nuclear weapon design Intelligence gathering Code-breaking Supercomputer General-purpose computer Solves individual problems at high speeds, compared with contemporary systems Typically costs $10 million or more Traditionally found in government labs Commercial Supercomputing Started in capital-intensive industries Petroleum exploration Automobile manufacturing Other companies followed suit Pharmaceutical design Consumer products 50 Years of Speed Increases CPUs 1 Million Times Faster Faster clock speeds Greater system concurrency Multiple functional units Concurrent instruction execution Speculative instruction execution Systems 1 Billion Times Faster Processors are 1 million ti