Tuning the Efficiency of Parallel Adaptive Integration with Synchronizers

High efficiency in parallel adaptive integration is difficult to achieve. Dependencies between integration regions are dynamic and therefore dynamic region redistribution is necessary. In our approach, we employ a control infrastructure designed to support parallel application global state monitoring. It includes monitors (called synchronizers), which observe application global states and take control decisions based on predicates computed on global states. Region redistribution strategy is implemented inside the monitors. The most and least loaded processes are selected and ordered to level their loads by region exchange. The paper shows that this strategy can work well, underlining some important factors, which influence the performance. Two methods, which aim at eliminating excessive region transfers, are presented. It is also shown, that good parallel efficiency can be obtained easier if interprocessor network supports efficient transmissions of large data packets. The problem of finding an optimal communication frequency between computing processes has been much reduced - it is enough if processes report their local load reasonably often.