Research On Nested Transactional Memory Of Object-oriented Program

Along with the development of the semiconductor manufacturing and the in-depth research of the processor architecture, multi-core processor has become an important direction of development, and has become the mainstream server and desktop. At the same time, how to progress multi-threaded programming based on multi-core, to find a better alternative mechanism for the lock mechanism have become a research topic. Transactional memory is a good choice.At present, there are two main mechanisms to achieve transactional memory: hardware and software. This paper presents the architecture of software transactional memory for object-oriented program, given a detailed definition and state conversion of transactional memory. And the paper presents three conflict resolution policies: immediate policy, delay policy and policy based on priority. As the most simple, basic strategy, immediate policy is used as the baseline of the performance comparison of the other two policies. Delay policy is using the beginning time for judge criteria of the importance of transactional memory, and operation workload for policy based on priority. Also, in order to provide the semantic nested transaction, this paper proposes nested transaction memory model, with abstract lock mechanism and compensation mechanism to implement nested transaction.Finally, this paper does experiments on the Intel dual-core, quad-core and two quad-core platform to test the performance of three conflict resolution policies as well as nested transaction. As the experiment results shown, delay policy and policy based on priority can get 20 percent and 25 percent performance improvement respectively. On the other hand, the performance of nested transaction enhances obviously, especially when having much core in processor.