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Hiroyuki Okuno

Scho ol of Information Science,

Japan Advanced Institute of Science and Technology

February 13, 1998

Keywords: WorkstationCluster,Performance Evaluation,Message PassingLibrary,

ParallelProcessing.

1 Introduction

Workstation cluster systems are very attractive for distributed and parallel processing,

sinceitiseasytoobtainparallelprocessingenvironment. Butsuchasworkstationclusters

using slownetworklayerhave aproblem that can not obtainperformances inprop ortion

to numb erof workstations.

In this paper, wediscuss ab out performance of messagepassing library such asPVM

and MPI, and propose hierarchical broadcast, a technique to to improvement PVM's

broadcast. Next we examine some applications on workstation cluster and discuss the

performance of workstation cluster. From the result, we discuss ab out applications run-

ning onworkstation cluster. Finally, we propose eectiveparallel processing method on

workstation clustersuchas sharedvalue system onPVM.

2 Workstation cluster and Massage passing libraly

Recently,manystudiesand approachesareexaminedtoimproveperformance ofworksta-

tion cluster. From hardware improvment,high-sp eed networklayers, suchas 100Base-T,

FDDI, ATM and Myrinet are deveropp ed. These hardwares achievesfaster workstation

cluster'smessagepassing. But,theircostofintro duction ishigh. Sowecannotuseeasily.

On the other hand, software approaches are performed to extend existed message

passinglibrary,suchasPVMand MPItoreducetheiroverheadonmessagepassingsetup

time. TPVM and LPVM are proposed this approach. pardi-PVM achieved fast message

passing using Adsmith proposed to provide new interfaces to PVM such as distributed

shared memory-systems.

Copyright c

1998byHiroyukiOkuno

interface.

3 Message passing performance on workstation clus-

ter

We measured message passing function's performance such as barrier synchronization,

latency, communication speed, and broadcast speed on workstation cluster, to propose

eectiveprocessingmethodusingworkstationclusterconstructedstandard PVMorMPI,

and 10Base-Tnetworks. This measurementisimp ortant toanalyze b ottlenecksonwork-

station clustr'smessage passing performance.

As the result, we found that PVM's message passing p erformance are good in case

of using TCP connection. MPI is better than PVM about all messagepassing functions.

From these message passing performance, we propose hierarchical broadcast to improve

PVM's broadcast speed, and conrmed their eectiveness. And we propose selectable

broadcast that improveshierachicalbroadcast.

4 Performance of Application programs on Work-

station Cluster

Inthis chapter,weexamineperformance ofworkstationcluster byrunningsome applica-

tions,suchassortingprogram, N-queen problemand TSP(Traveling SalesmanProblem).

We found sorting program is unsuitable on workstation cluster because sort program

communicatewith large data due to increasing message passing time. N-queen problem

indicated that if non-communication parallel processing model could load tasks equally,

performance will increase linearly. In TSP,weexamined and discussed some parallel ex-

ecutionmethod,suchas distributed mo del, master-slavemodel, and co-operationmodel.

We gained co-operation model achieves linear performance increase. And wefound that

TSP is not aected by message passing,so suitablefor workstationclusters. As aresult,

we proposedshared value system tomake availableshared valueusing PVM.

5 Conclusion

Thispaperevaluatedworkstationclusterperformanceanddiscussedtheircharacters. We

found workstationcluster usingslownetworklayersuchas 10Base-T,arenot appropriate

tocommunicatlargedata. Fromthat'sresult,weproposedhierarchicalbroadcastonPVM

and conrmedimprovementofbroad castperformance. Wediscussedabout performance

of applicationsrunningon workstationcluster. As the result,wegaind thatless message

passing model and less message data passing model is suitable for workstation cluster.

And we proposed and discussed about shared value system which makes shared value

system on PVM.

tem prop osed inthis pap er and evaluation their performance.