Pro cs ZEUS Workshop on Par Programming and Computation Link oping Sweden
Portabilityversus E ciency
Parallel Applications on PVM and Parix
Alexander Reinefeld Volker Schnecke
Center for Parallel Computing Mathematik Informatik
Universit at Paderb orn Universit at Osnabruc k
ar uni paderb orn de volker informatik uni osnabrueck de
Abstract
Analogous to the shift from assembler language programming to the third
generation languages in the early years of computer science we are currently wit
nessing a paradigm change towards the use of p ortable programming mo dels in
parallel high p erformance computing Like b efore the use of a high level program
ming environmentmust b e paid for by a reduced system p erformance
But howmuch do es p ortability cost in practice Is it worth paying that price
What e ect has the choice of the programming mo del on the algorithm architecture
In this pap er we attempt to answer these questions by comparing two applica
tions from the domain of combinatorial optimization that have b een implemented
with the Parix and PVM programming mo dels Performance b enchmarks have
b een run on three di erent systems a massively parallel transputer system with
relatively slow T pro cessors a mo derately parallel Parsytec GC PowerPlus sys
tem with p owerful MFLOPS pro cessors and a UNIX workstation cluster con
y a Mbps LAN While the Parix implementations clearly turned out to b e nected b
fastest PVM gives p ortability at the cost of a small acceptable loss in p erformance