On algorithm design and programming model for multi-threaded computing

Abstract

The objective of this work is to investigate the algorithm design and the programming model of multi-threaded computing. Designing multi-threaded algorithms is very challenging - when multiple threads need to communicate or coordinate with each other, efficient synchronization support is needed. However, synchronizations are known to be expensive on the emerging multi-/many-core processors, especially when the number of threads increases. To fully unleash the power of such processors, carefully investigations are needed in both algorithm design and programming models for multi-threaded systems.

In this dissertation, we first present an asynchronous multi-threaded algorithm for the maximum network flow problem. This algorithm is based on the classical push-relabel algorithm and completely removes the use of locks and barriers from its original parallel version. While this algorithmic method shows effectiveness, it is challenging to generalize the success to other multi-threaded problem. We next focus on improving the transactional memory, a promising mechanism to construct multi-threaded programs. A queuing-theory-based model is developed to analyze the performance of different transactional memory systems. Based on the results of the model, we emphasize on the contention management mechanism of transactional memory systems. A profiling-based adaptive contention management scheme is finally proposed to cope with the problem that none of the static contention management schemes can keep good performance on all platforms for all types of workload. From this research, we show that it is necessary and worthwhile to explore both the algorithm design aspect and the programming model aspect for multi-thread computing.