\begin{abstract}
\noindent Performance tuning programs for dataflow execution involves
tradeoffs and optimizations which may be significantly different than for
execution on conventional machines.  We examine some tuning techniques for
scientific programs with regular control but irregular geometry.  We use as
an example the core of an ocean modeling code developed in the implicitly
parallel language Id for the Monsoon dataflow machine.  Dataflow
implementations of loops, in particular, require careful examination by the
compiler or programmer to attain high performance because of overheads due
to fine-grained synchronization, control, and operand distribution.
\end{abstract}
