Technical Report CAMAS - TR - 2 . 3 . 4

This document reports on the design and implementation considerations of PVM/PARIX, homogeneous version 1.0. This version is for use with PARIX 1.2 only. Further, it contains information how to use Homogeneous PVM/PARIX and the appendix contains the installation notes. 1 What Is Homogeneous PVM/PARIX? The popularity of PVM nowadays, can be partly explained by the inherent portability of PVM programs over a large number of parallel systems. The spectrum of parallel systems consists from loosely coupled networks with remote shell capabilities, via parallel clusters, to MPP architectures. The use of PVM as a parallel programming environment for MPP architectures, raises the following observation. The heterogeneity which made PVM so popular in the beginning, now seems a drawback in the application of PVM to MPP architectures due to the large overhead to handle this heterogeneity. This is especially true for the communication primitives, e.g., communication latencies between processes inside the MPP can become quite large. This has motivated the development of a so-called homogeneous version of PVM for the PARIX parallel operating system. This PVM/PARIX version has the additive homogeneous version, which essentially means that all PVM processes are to be run on the MPP system only. Thus, the parallel virtual machine can only consist of the nodes in the Parsytec MPP, and PVM inter-process communication with the front-end system is not supported (of course I/O with the front-end is possible, this is handled by PARIX). It is therefore not possible to send messages to PVM tasks outside the MPP. The large advantage however, is that the communication latency and throughput will be improved drastically, resulting in a communication performance which is almost as fast as the underlying PARIX layer. The user interface of this Homogeneous PVM/PARIX version is somehow different than with the standard PVM. There is no console present, for example to start a virtual machine, and the Homogenous PVM/PARIX programs are issued as normal PARIX programs, e.g., with the run or hpvmrun script (see also Section 4).