Masahiko Ikawa

Improvement of message communication in concurrent logic language

In the execution of concurrent logic language KL1 on messagepassing multiprocessors, frequent fine-grained communicantions cause a drastic inefficiency. We propose an opt imization scheme which achieves high granularity of messages by packing data transfer. Using static analysis, we derive the data typea which are required by the receiver procaa. With this information, each data of these types are packed into large messages. As a result of evaluation, the number of communications was considerably reduced. This effects to reduce the execution time of programs whkh have large communication overhead.

Efficient Goal Scheduling in Concurrent Logic Language using Type-Based Dependency Analysis

In the execution model of concurrent logic languages like KL1, each goal is regarded as a unit of concurrent execution. Although this fine-grained concurrency control enables flexible concurrent/parallel programming, its overhead also causes inefficiency in its implementation. We propose an efficient goal scheduling scheme using the result of static analysis. In this scheme, we obtain precise dependency relations among goals using type-based dependency analysis. Then each set of goals without concurrency is compiled into one thread, a sequence of statically ordered goals, to reduce the overhead of goal scheduling. Since stacks are used to hold goal environments for each thread, the number of garbage collection is also reduced. The result of preliminary evaluation shows our scheme considerably reduces goal scheduling overhead and thus it achieves 1.3–3 times speedup.