Boris Weissman

Performance counters and state sharing annotations: a unified approach to thread locality

This paper describes a combined approach for improving thread locality that uses the bardware performance monitors of modem processors and program-centric code annotations to guide thread scheduling on SMPs. The approach relies on a shared state cache model to compute expected thread footprints in the cache on-line. The accuracy of the model has been analyzed by simmations involving a set of parallel applications. We demonstrate how the cache model can be used to implement several practical locality-based thread scheduling policies with little overhead. Active Threads, a portable, high-performance thread system, has been built and used to investigate the performance impact of locality scheduling for several applications.

Efficient fine-grain thread migration with active threads

Thread migration is established as a mechanism for achieving dynamic load sharing. However, fine-grained migration has not been used due to the high thread and messaging overheads. This paper describes a fine-grained thread migration system whose extensible event mechanism permits an efficient interface between threads and communications without compromising the modularity and performance of either. Migration is supported by user level primitives based on which applications may implement different migration policies. The system is portable and can be used directly or serve as a compilation target for parallel languages. The system runs on a cluster of SMPs and observed performance is orders of magnitude better than other reported measurements.