Commercial Relational Database Systems have

Simultaneous Multi-threading (SMT) has been developed to increase instruction level parallelism by allowing instructions from a different thread to run during a stall. Inter-thread cache interference, however, might limit the benefit of running multiple independent threads. SMT processors can be utilized in a different model, where a helper thread is used to prefetch cache blocks for the main execution thread. Physical experimentation with low level compiler generated prefetch threads has been tried with mixed results. Memory resident databases spent as much as 50 % their time in stalls. Memory prefetching has been shown to have a positive effect in some situations. In this paper we present an experiment with an abstracted database operation which uses a high level synchronized thread mechanism to prefetch memory. The experiment run on an Intel Pentium 4 processor with Hyper-Threading. The focus of the experiment was the L2 cache performance. The results show a substantial decrease of L2 misses as reported by Pentium 4 Performance Monitoring. Additionally, a main/prefetch thread pair can be made to run 15 % faster than a single thread, in spite of the high synchronization cost