基于消息传递的并行计算.ppt

* * * Defines the scope of a communication operation. Processes have ranks associated with the communicator. Initially, all processes enrolled in a “universe” called MPI_COMM_WORLD, and each process is given a unique rank, a number from 0 to n - 1, where there are n processes. Other communicators can be established for groups of processes. * * * * * * * * * * * * 例如, MPI-2增加了进程管理功能, 而现在的PVM也提供了更多的群集通信函数. * * * * * * * * * * * * * * * * XPVM provides point-and-click access to the PVM console commands. A pull-down menu allows users to add or delete hosts to configure the virtual machine. Tasks can be spawned using a dialog box that prompts for all spawn options, including the trace mask to determine which PVM routines to trace for XPVM. * The Network View displays high-level activity on the hosts in the Virtual Machine. Each host is represented by an icon image which includes the architecture and name of the host. These icons are illuminated in different colors to indicate the status of the tasks running on each host. The Active color implies that at least one task on that host is busy executing useful work. The System color means that no tasks are busy executing user computation, but that at least one task is busy executing PVM system routines. When there are no tasks on a given hosts, its icon is left uncolored, or white. The specific colors used in each case default to green for active and yellow for system, but are user customizable. * The Space-Time View shows the status of individual tasks as they execute across all hosts. Each task is represented by a horizontal bar along a common time axis, where the color of the bar at each time indicates the state of the task. The Computing color shows those times when the task is busy executing useful user computations. The Overhead color marks the places where the task executes PVM system routines for communication, task control, etc. The Waiting color indicates those time periods spent waiting for messages from other