Research On Conflict Management Strategies In Multicore-oriented Software Transactional Memory

The current development of multicore processors is rapid, but the design of parallel program is seriously lagging behind and it can’t take full advantage of multicore processors. Under this situation, tansancational memory comes into being. Transactional memory allows atomic transaction blocks to execute concurrently, and execute serially when transactions meet conflict. Transancational memory system is a new multicore architecture and provides an efficient parallel programming environment for parallel programmers. Using of transaction can solve a series of problems which are caused by lock mechanism, and can improve the concurrency of program.In this thesis, conflict management strategies are mainly studied. Conflict detection and conflict resolution are included in conflict management strategies. Conflict detection has an important influence on the performance of system. Some current conflict detection algorithms based on Signature which have better performance are analysed in this thesis, and they are improved by combinating the advantages of VHB and True-Bloom algorithm to propose VHTB algorithm. The advantage of VHTB algorithm is that VHTB algorithm uses the storage which VHB algorithm has not used to store the mapping of True-Bloom algorithm. The performance of VHTB algorithm is tested in real software transactional memory system. Experimental results show that VHTB algorithm has a lower rate of transaction aborts compared with VHB algorithm. Conflict resolution is a major part of conflict management strategies. In this thesis, by the study of conflict resolution strategies in Rochester software transactional memory (RSTM), Comprehensive conflict resolution strategy is proposed and implemented. Comprehensive conflict resolution strategy is a compound conflict resolution strategy based on RSTM. When two transactions conflict, the discard costs, number of tries, start time and other factors are considered together to decide which transaction should be aborted. Some benchmarks of RSTM are used to test the performance of Comprehensive conflict resolution strategy. Experimental results show that Comprehensive conflict resolution strategy can exhitibt relatively better performance in most cases. In this thesis, firstly, the research background and related technologies are mentioned. Then two strategies about conflict management techniques are proposed. The two strategies include VHTB algorithm based on Signature and Comprehensive conflict resolution strategy. The performance of the two strategies is tested at the same time. At last, the work in this thesis is summarized and the further steps are prospected.