并行Chapter2资料.ppt

Chapter 2 Message-passing Computer Basic of message-passing programming Using workstation clusters Evaluating parallel programs Debugging and evaluating parallel programs 2.1 BASIC OF MESSAGE-PASING PROGRAMMING Programming options Process creation Message-passing routines 2.1.1 Programming Options A special parallel programming language Extending the syntax/reserved words of an existing sequential high-level language to handle message passing. Using a special parallelizing compiler to convert a program written in a sequential programming language into executable parallel code. Using an existing sequential high-level language and providing a library of external procedure for message passing 2.1.2 Process Creation Static process creation Dynamic process creation 1. static process creation All the processes are specified before execution. System will execute a fixed number of processes. The most general model:SPMD(single program multiple data). The different processes are merged into one program; Control statements select different parts for each process. Each processor will load a copy of the“same”code (executable) into its local memory for execution. 2.1.2 Process Creation 2. Dynamic process creation Processes can be created and their execution initiated during the execution of other processes. processes can also be destroyed.The number of processes may vary during execution. Model:MPMD(multiple program multiple data). A completely separate and different program is written for different processors. It does incur very significant overhead when the processes are created. The master-slave approach is usually taken whereby a single processor executes a master program(the master process)and other processes are started from within the master process. 2.1.3 Message-Passing Routines 1、Basic send and receive routines(point-to-point) 2、Synchronous message passing 3、Asynchronous message passing 4、Message selection 5、Group Routines : Boardcast、Gather、Sc