Strategies for scheduling and- and or- work in parallel logic programming systems
Inês Dutra · 1994
Recent parallel logic programming systems, such as Andorra-I, can exploit multiple forms of parallelism, and- and or-parallelism, in logic programs. In order to effectively exploit both kinds of parallelism, such systems must address one problem not yet tackled in logic programming systems, namely how to distribute resources between two different kinds of parallel work, andand or-work. This paper proposes solutions to this problem. We present two dynamic scheduling strategies to distribute and- and or-work in parallel logic programming systems. One strategy, work-based, guides its decisions by looking at the amount of current and- and or-work available in an application during execution. The other strategy, efficiency-based, is designed around the intuition that workers should spend most of their execution time doing useful work, i.e., performing reductions. Results show that both strategies work reasonably well when both kinds of parallelism are available. Both strategies could be app...